Optical measurement system and method

Abstract

The invention relates to an optical measurement system and method. The present disclosure relates to embodiments of an optical measurement system configured to perform spectral measurements. The optical measurement system is configured to provide a compact arrangement for introducing light into a sample and collecting light returning from the sample. Reducing the size of the transmit architecture and / or the collection architecture of the optical measurement system may make the entire optical measurement system smaller, providing flexibility in integrating the optical measurement system into various form factors.

Description

Technical Field

[0001] The present disclosure generally relates to optical measurement systems configured to introduce light into a sample and collect light returned from the sample, and more particularly to optical measurement systems that use the light to perform spectroscopic measurements. Background Art

[0002] Optical measurement systems can be used to identify the presence, type, and / or one or more characteristics of objects or substances in the system's surrounding environment. In some cases, optical measurement systems can perform spectroscopic measurements by emitting light at multiple wavelengths and measuring the light returning to the system. The relative amount of light returned at each wavelength can provide information about the properties of one or more materials being measured. The amount of light returning to the optical measurement system can also depend on the optical path length of the light within the sample. To help improve the accuracy of measurements performed by the optical measurement system, it may be desirable to control the range and distribution of the optical path length of the light emitted by the optical measurement system within the sample. As the number of wavelengths measured by the optical measurement system and the number of unique measurement locations each increase, these optical measurement systems may require increasingly complex architectures to perform accurate measurements. Consequently, there may be a need for compact optical measurement systems with improved optical path length control. Summary of the Invention

[0003]

[0014] Embodiments of the systems, devices, methods, and apparatus described in this disclosure relate to optical measurement systems, and components and measurement subsystems thereof, configured to determine one or more properties of a sample via spectroscopic measurements.

[0004] Some embodiments described herein relate to an optical measurement system comprising: a sampling interface defining a transmission site and a set of collection sites, each collection site laterally spaced from the transmission site; a transmission architecture configured to transmit an emission beam that exits the sampling interface through the transmission site; and a collection architecture comprising a set of detector elements positioned to measure light that has entered the sampling interface through the set of collection sites. When the transmission architecture transmits the emission beam, the set of detector elements can form a set of measurement channels. The emission beam converges in a first dimension upon exiting the sampling interface, and when the emission beam is emitted into a target sample, the emission beam projects into a transition region in the target sample that is angularly independent of at least one of the set of measurement channels.

[0005] Other embodiments relate to an optical measurement system comprising: a sampling interface defining a transmission site and a first collection site laterally spaced from the transmission site; a transmission architecture configured to transmit an emission beam that exits the sampling interface through the transmission site; and a collection architecture comprising a first detector element. The collection architecture is configured to collect a first return beam that enters the sampling interface through the first collection site and direct the return beam to the first detector element. When the transmission architecture transmits the emission beam, the first detector element forms a first measurement channel, the first return beam diverges in a first dimension upon entering the sampling interface, and, when the first return beam is collected from a target sample, is projected from a first transition region in the target sample that is angularly independent of the first measurement channel.

[0006] Yet other embodiments relate to an optical measurement system comprising: a sampling interface defining a transmission site and a first collection site laterally spaced from the transmission site; a transmission architecture configured to transmit an emission beam that exits the sampling interface through the transmission site; and a collection architecture comprising a first detector element. The collection architecture is configured to collect a first return beam that enters the first sampling interface through the collection site and direct the return beam to the first detector element. When the transmission architecture transmits the emission beam, the first detector element forms a measurement channel, the emission beam converging in a first dimension upon exiting the sampling interface and the return beam diverging in the first dimension upon entering the sampling interface. The optical measurement system is configured such that, when the optical measurement system is used to measure a characteristic of a target sample, the emission beam is projected into a first transition region in the target sample that is independent of the angle of the measurement channel, and the return beam is projected from a second transition region in the target sample that is independent of the angle of the measurement channel.

[0007] In some embodiments, an optical measurement system includes: a sampling interface defining a transmission site and a set of collection sites, each collection site laterally spaced from the transmission site; a transmission architecture configured to transmit an emission light beam that exits the sampling interface through the transmission site and enters a sample under test; and a collection architecture comprising a set of detector elements positioned to measure light that has entered the sampling interface through the set of collection sites. The emission light beam converges in a first dimension as it exits the sampling interface and is projected into a transition region in the sample under test. The transmission architecture includes: a beam generator comprising a light source unit and configured to generate a diverging output light beam; and a transmission optical subassembly configured to collimate the diverging input light beam in the first dimension to generate a plurality of collimated light beams that collectively form the emission light beam and are projected to intersect at the transition region.

[0008] Other embodiments relate to an optical measurement system comprising: a sampling interface defining a transmission site and a set of collection sites, each collection site laterally spaced from the transmission site; a transmission architecture; and a collection architecture. The transmission architecture comprises: a diffuser positioned to receive an input light beam and generate an output light beam that diverges in a first dimension; and a set of lenses configured to collimate the diverging output light beam in the first dimension to generate an emission light beam that converges in the first dimension. The collection architecture comprises a set of detector elements positioned to measure light that has entered the sampling interface through the set of collection sites. The emission light beam is formed by a plurality of collimated light beams that are projected to intersect at a transition region in a sample being measured as the emission light beam exits the transmission site.

[0009] In some cases, an optical measurement system may include: a sampling interface defining a transmission site and a set of collection sites, each collection site laterally spaced from the transmission site; a transmission architecture; and a collection architecture. The transmission architecture includes: a photonic integrated circuit configured to generate an input light beam; a diffuser positioned to receive the input light beam and generate an output light beam diverging in a first dimension; and a set of lenses configured to generate a plurality of collimated light beams from the output light beam, the plurality of collimated light beams being projected to intersect at a transition region in a sample under measurement. The collection architecture includes a set of detector elements positioned to measure light that has entered the sampling interface through the set of collection sites.

[0010] Yet other embodiments relate to an optical measurement system comprising: a sampling interface defining a transmission site and a first collection site laterally spaced from the transmission site; a transmission architecture configured to transmit an emission beam that exits the sampling interface through the transmission site; and a collection architecture comprising a first optical collection subassembly having a first condenser lens and a first plurality of detector elements. The collection architecture is configured to collect a first return beam from the first collection site and direct the first return beam to the first condenser lens, with each detector of the first plurality of detector elements measuring a corresponding portion of the first return beam to form a corresponding measurement channel of a first plurality of measurement channels. Furthermore, the first return beam diverges in a first dimension upon entering the first collection site, and when the first return beam is collected from a target sample, the first return beam is projected from a first transition region in the target sample that is angularly independent of each measurement channel of the first plurality of measurement channels.

[0011] In some embodiments, an optical measurement system includes: a sampling interface defining a transmission site and a collection site laterally spaced from the transmission site; a transmission architecture configured to transmit an emission light beam that exits the sampling interface through the transmission site; and a collection architecture comprising: an optical collection subassembly including a plurality of condenser lenses; and a plurality of groups of detector elements. Each group of detector elements in the plurality of groups of detector elements is positioned to receive light from a corresponding condenser lens in the plurality of condenser lenses. The collection architecture is configured to collect a plurality of return light beams that enter the sampling interface through the collection site. The collection architecture is configured to direct a portion of each of the plurality of return light beams to each of the plurality of condenser lenses so that each of the plurality of detector elements measures light from each of the plurality of light beams.

[0012] In other embodiments, an optical measurement system includes: a sampling interface defining a transmission site and a first collection site laterally spaced from the transmission site; a transmission architecture configured to transmit an emission light beam that exits the sampling interface through the transmission site; and a collection architecture. The collection architecture includes: a first optical collection subassembly including a first condenser lens and configured to receive light that returns to the sampling interface through the first collection site; and a first plurality of detector elements positioned to receive light from the first condenser lens. The collection architecture is configured such that, when the collection architecture receives light from a target sample, each of the first plurality of detector elements measures light having a first common path length distribution and a different sampling depth distribution.

[0013] Still further embodiments relate to an electromagnetic actuator arrangement comprising a fixed base, a set of suspension elements, a carrier movably connected to the fixed base via the set of suspension elements, and a first diffuser carried by the carrier. The electromagnetic actuator arrangement further comprises a set of actuators mounted to the carrier and controllable to move the carrier relative to the fixed base. The carrier defines a first carrier aperture extending through the carrier.

[0014] In other embodiments, an optical measurement system includes a sampling interface defining a transmission site and a first collection site laterally spaced from the transmission site; and a transmission architecture configured to transmit a transmission light beam that exits the sampling interface through the transmission site, wherein the transmission architecture includes a beam generator including a diffuser. The diffuser is positioned to receive an input light beam and generate an output light beam that diverges in a first dimension. The optical measurement system includes a collection architecture having a first set of detector elements positioned to measure light that has entered the sampling interface through the first collection site. The optical measurement system also includes an electromagnetic actuator arrangement having a fixed base, a carrier movably connected to the fixed base, and a set of actuators mounted to the carrier and controllable to move the carrier relative to the fixed base. The diffuser is carried by the carrier, the carrier defining a first carrier aperture extending through the carrier, and the first carrier aperture is positioned such that light measured by the first set of detector elements passes through the first carrier aperture.

[0015] In some embodiments, the optical measurement system includes a first measurement subsystem configured to transmit a first emission beam into a sample through a sampling interface and to measure a portion of the first emission beam returned from the sample through the sampling interface. The optical measurement system also includes a second measurement subsystem configured to transmit a second emission beam into the sample through the sampling interface and to measure a portion of the second emission beam returned from the sample through the sampling interface. The optical measurement system also includes an electromagnetic actuator arrangement having a fixed base, a carrier movably connected to the fixed base, and a set of actuators mounted to the carrier and controllable to move the carrier relative to the fixed base. The first measurement subsystem includes a first diffuser, the second measurement subsystem includes a second diffuser, and the carrier carries the first diffuser and the second diffuser.

[0016] Other embodiments relate to a polarizing beam splitter comprising: a substrate comprising a top surface and a bottom surface; and a polarizer positioned on a first portion of the bottom surface. The top surface defines a first angled facet. The polarizing beam splitter is configured such that when an incident light beam is incident on a predetermined location of the bottom surface at a predetermined angle of incidence: the polarizer generates a polarized light beam from the incident light beam, the first angled facet splits the polarized light beam into a first split light beam and a second split light beam, the first split light beam exits the polarizing beam splitter through the first angled facet, and at least a portion of the second split light beam exits the polarizing beam splitter through the bottom surface.

[0017] In some embodiments, a polarizing beam splitter includes: a substrate including a top surface and a bottom surface; and a polarizer positioned on a first portion of the bottom surface. The top surface defines a first angled facet and a second angled facet. The polarizing beam splitter is configured such that when an incident light beam is incident on a predetermined location of the bottom surface at a predetermined angle of incidence: the polarizer generates a polarized light beam from the incident light beam, the first angled facet splits the polarized light beam into a first split light beam and a second split light beam, the first split light beam exits the polarizing beam splitter through the first angled facet, and at least a portion of the second split light beam exits the polarizing beam splitter through the top surface.

[0018] In yet other embodiments, an optical measurement system includes: a sampling interface defining a transmission site and a set of collection sites, each collection site laterally spaced from the transmission site; a transmission architecture including a beam generator and configured to transmit an emission beam that exits the sampling interface through the transmission site and enters a sample under test; and a collection architecture including a set of detector elements positioned to measure light that has entered the sampling interface through the set of collection sites. The beam generator is configured to generate an input beam and an output beam from the input beam, the transmission architecture is configured to generate an emission beam from the output beam, and the beam generator includes a reference detector and a polarizing beam splitter. The polarizing beam splitter includes: a substrate having a top surface and a bottom surface, the top surface defining a first angled facet; and a polarizer positioned on a first portion of the bottom surface. The polarizing beam splitter is positioned to receive an input beam passed through the polarizer to generate a polarized beam, and is configured to split the polarized beam into a first split beam and a second split beam. A beam generator generates an output beam from the first split beam, and a reference detector is positioned to measure at least a portion of the second split beam.

[0019] In some embodiments, a beam shifting optic includes a substrate comprising a top surface and a bottom surface, wherein the bottom surface defines at least one angled facet that is angled in a first dimension, and the top surface defines a lens facet that is curved in a second dimension perpendicular to the first dimension. The beam shifting optic is configured such that when a light beam enters the beam shifting optic through a predetermined input region and at a predetermined angle of incidence: the light beam reflects off the at least one angled facet to redirect the light beam in the first dimension, and the light beam exits the beam shifting optic through an exit region of the lens facet to at least partially collimate the light beam.

[0020] Other embodiments relate to a beam generator configured to generate an output beam. The beam generator includes a photonic integrated circuit configured to emit an input beam; a beam shifting optical device; and a diffuser positioned to receive the input beam and generate an output beam from the input beam. The beam shifting optical device is positioned to receive the input beam at a predetermined input region and at a predetermined angle of incidence, and is configured to laterally shift the input beam in a first dimension. The beam shifting optical device has a substrate having a top surface and a bottom surface, such that the bottom surface defines a first angled facet that is angled in the first dimension. The beam shifting optical device is configured such that when the input beam enters the beam shifting optical device through the predetermined input region and at the predetermined angle of incidence, the beam reflects off the first angled facet to redirect the beam in the first dimension, and the beam exits the beam shifting optical device through an exit region of the beam shifting optical device.

[0021] Yet other embodiments relate to an optical measurement system comprising: a sampling interface defining a transmission site and a set of collection sites, each collection site laterally spaced from the transmission site; a transmission architecture comprising a beam generator configured to transmit a transmission beam that exits the sampling interface through the transmission site and enters a sample under test; and a collection architecture comprising a set of detector elements positioned to measure light that has entered the sampling interface through the set of collection sites. The beam generator is configured to generate an input beam and an output beam from the input beam. The transmission architecture is configured to generate the transmission beam from the output beam. The beam generator comprises a photonic integrated circuit configured to transmit the input beam; and beam shifting optics configured to laterally shift the input beam in a first dimension.

[0022] In some embodiments, an optical measurement system includes a first measurement subsystem configured to transmit a first emission beam into a sample through a sampling interface and to measure a portion of the first emission beam that returns from the sample through the sampling interface. The optical measurement system also includes a second measurement subsystem configured to transmit a second emission beam into the sample through the sampling interface and to measure a portion of the second emission beam that returns from the sample through the sampling interface. The optical measurement system includes: a set of photonic integrated circuits configured to transmit a first input beam and a second input beam; and an electromagnetic actuator arrangement comprising a fixed base, a carrier movably coupled to the fixed base, and at least one diffuser carried by the carrier. The first input beam is routed through the at least one diffuser to generate a first output beam, and the second input beam is routed through the at least one diffuser to generate a second output beam. The first measurement subsystem generates a first emission beam from the first output beam, and the second measurement subsystem generates a second emission beam from the second output beam.

[0023] Other embodiments relate to an optical system comprising a first measurement subsystem configured to transmit a first emission beam into a sample through a sampling interface and to measure a portion of the first emission beam that returns from the sample through the sampling interface. The optical measurement system also comprises a second measurement subsystem configured to transmit a second emission beam into the sample through the sampling interface and to measure a portion of the second emission beam that returns from the sample through the sampling interface. The optical measurement system comprises a photonic integrated circuit configured to transmit a first input beam from a first emission location on the photonic integrated circuit and a beam redirection structure configured to route light from the first input beam between the first measurement subsystem and the second measurement subsystem.

[0024] Yet other embodiments relate to an optical measurement system comprising a first measurement subsystem configured to transmit a first emission beam into a sample through a sampling interface and to measure a portion of the first emission beam that returns from the sample through the sampling interface. The optical measurement system also comprises a second measurement subsystem configured to transmit a second emission beam into the sample through the sampling interface and to measure a portion of the second emission beam that returns from the sample through the sampling interface. The optical measurement system comprises a photonic integrated circuit configured to transmit a first input beam and a second input beam from a common surface of the photonic integrated circuit. The first measurement subsystem is configured to generate a first output beam from the first input beam, and the second measurement subsystem is configured to generate a second output beam from the first input beam. The first output beam and the second output beam are generated in an interleaved relationship relative to the photonic integrated circuit.

[0025] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following descriptions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present disclosure will be readily understood through the following detailed description in conjunction with the accompanying drawings, in which like reference numerals represent like structural elements and in which:

[0027] Figure 1A Shown is a cross-sectional side view of a device incorporating an optical measurement system as described herein. Figure 1B Shown Figure 1A view of your equipment.

[0028] Figure 2A and Figure 2B Shown are partial cross-sectional side views of two variations of optical measurement systems, each having measurement channels configured with a different path length distribution. Figure 2C Shown Figure 2A and Figure 2B Plot of an example path length distribution of a measurement channel of an optical measurement system.

[0029] Figure 3A A partial cross-sectional side view of a portion of an optical measurement system configured to emit a transmission light beam is shown. Figure 3B Shown Figure 3A A perspective view of a part of the optical measurement system.

[0030] Figure 4A 、 Figure 4B 、 Figure 4D and Figure 4E A partial cross-sectional view of an optical measurement system for measuring a target sample as described herein is shown. Figure 4C and Figure 4F Shown Figure 4A 、 Figure 4B 、 Figure 4D and Figure 4E Plot of an example path length distribution of a measurement channel of an optical measurement system.

[0031] Figure 5A A partial cross-sectional side view of a portion of an optical measurement system configured to collect a return light beam is shown. Figure 5B Shown Figure 5A A perspective view of a part of the optical measurement system.

[0032] Figure 6A and Figure 6B A partial cross-sectional view of a variation of an optical measurement system for measuring a target sample as described herein is shown.

[0033] Figure 7 A partial cross-sectional side view of an optical measurement system configured to project light toward a sample region that is angularly independent of a first measurement channel is shown.

[0034] Figure 8 A partial cross-sectional side view of an optical measurement system configured to collect light projected to emanate from a sample region independent of an angle with respect to a first measurement channel is shown.

[0035] Figures 9A to 9C A partial cross-sectional side view of a variation of an optical measurement system is shown that is configured to project light toward a first sample region that is angularly independent of at least one measurement channel and to collect light that is projected to emanate from a second sample region that is angularly independent of some or all of the at least one measurement channel. Figure 9D Shown Figure 9C Perspective view of the optical measurement system.

[0036] Figure 10A and Figure 10B Shown are side views of two variations of transmit architectures as described herein that are configured to generate a transmit light beam that converges in at least one dimension.

[0037] Figure 11A and Figure 11B Shown are side views of two variations of transmit architectures as described herein that are configured to set certain properties of a transmitted light beam.

[0038] Figure 12 A block diagram of an example beam generator that may be used with the optical measurement systems described herein to generate an output beam is shown.

[0039] Figure 13AShown is a top view of a variation of a transmit architecture that may be used with the optical measurement systems described herein. 13B to 13F Shown Figure 13A Side view of a variation of the transmit architecture.

[0040] Figure 14A 、 Figure 14C and Figure 14E Shown is a side view of a variation of a collection architecture that may be used with the optical measurement systems described herein. Figure 14B 、 Figure 14D and Figure 14F Shown respectively Figure 14A 、 Figure 14C and Figure 14E Plot of the measurement channel path length and sampling depth distribution for the collection architecture.

[0041] Figure 15A Shown is a side view of a variation of the collection architecture incorporating a condenser lens. Figure 15B Shown Figure 15A Plot of the measurement channel path length and sampling depth distribution for the collection architecture.

[0042] Figure 16A and Figure 16B Shown is a side view of a variation of a collection architecture incorporating multiple condenser lenses. Figure 16C Shown Figure 16A and Figure 16B Plot of the measurement channel path length and sampling depth distribution for the collection architecture.

[0043] Figure 17A A side view of another variation of a collection architecture incorporating multiple condenser lenses is shown. Figure 17B Shown Figure 17A Plot of the measurement channel path length and sampling depth distribution for the collection architecture.

[0044] 18A to 18C Shown is a partial top view of a collection architecture that may be used with the optical measurement systems described herein.

[0045] Figure 19A Shown is a top view of an example of an electromagnetic actuator arrangement that may be used with the optical measurement systems described herein. Figure 19B and Figure 19C Shown Figure 19A Cross-sectional side view of a variation of the electromagnetic actuator arrangement.

[0046] Figures 20A to 20E Shown is a top view of a variation of an electromagnetic actuator arrangement such as described herein comprising one or more carrier apertures.

[0047] Figure 21AShown is a side view of a portion of an optical measurement system including a variation of a polarizing beam splitter as described herein. Figure 21B Shown Figure 21A Perspective view of a polarizing beam splitter. Figure 21C and Figure 21D Shown are the combined Figure 21B Perspective view of the polarizing beam splitter, beam generator, and optical measurement system.

[0048] Figure 22A Shown is a side view of a portion of an optical measurement system including another variation of a polarizing beam splitter as described herein. Figure 22B and Figure 22C Shown Figure 22A Perspective view of a polarizing beam splitter.

[0049] Figures 23 to 26 Shown are side views of portions of optical measurement systems including different variations of polarizing beam splitters as described herein.

[0050] Figure 27A shows a side view of a variation of a beam-shifting optic having curved angled facets as described herein, and Figure 27B and Figure 27C A perspective view thereof is shown. Figure 27D Shown include Figures 27A to 27C A partial cross-sectional side view of a variation of the beam shifting optics for a beam generator.

[0051] Figure 28A and Figure 28B Shown are side and perspective views, respectively, of a variation of a beam-shifting optic having flat angled facets as described herein. Figure 28C and Figure 28D Shown include Figure 28A and Figure 28B Side view of a variation of the beam shifting optics for a beam generator.

[0052] Figure 29A and Figure 29B Shown are side and perspective views, respectively, of a variation of a beam shifting optic having a beam redirecting portion as described herein. Figure 29C Shown include Figure 29A and Figure 29B Side view of a variation of the beam shifting optics for a beam generator.

[0053] Figure 30A and Figure 30B Shown are side and bottom perspective views, respectively, of a variation of a beam-shifting optic having multiple angled facets on a common surface as described herein. Figure 30C Shown include Figure 30A and Figure 30B Side view of a variation of the beam shifting optics for a beam generator.

[0054] Figure 31A and Figure 31B Shown are side and bottom perspective views, respectively, of a variation of a beam shifting optic having multiple angled facets on each of the bottom and top surfaces as described herein.

[0055] Figure 32A shows a side view of a variation of a beam shifting optic having a lens output region as described herein, and Figure 32B and Figure 32C A perspective view thereof is shown. Figure 32D Shown include Figures 32A to 32C A partial cross-sectional side view of a variation of the beam shifting optics for a beam generator.

[0056] Figure 33A and Figure 33B Shown are side and perspective views, respectively, of a variation of a beam shifting optic having a lens output region and multiple angled facets on each of the bottom and top surfaces as described herein.

[0057] Figures 34A to 34C 、 Figures 35A to 35E 、 Figure 36 、 Figure 37A 、 Figure 37C 、 Figures 38A to 38D 、 Figure 39A and Figure 39B Shown is a top view of a variation of an optical measurement system having a photonic integrated circuit configured to emit multiple input light beams. Figure 37B Shown Figure 37A Side view of the optical measurement system.

[0058] Figure 40A Shown is a top view of a variation of an optical measurement system configured to generate different output beams from a common input beam. Figures 40B to 40E Shown Figure 40A Partial side view of a variation of the optical measurement system.

[0059] Figure 41A Shown is a top view of a variation of an optical measurement system including an array of mirrors configured to route different input light beams. Figure 41B and Figure 41C Shown Figure 41A Partial side view of a variation of the optical measurement system.

[0060] Figure 42A Shown is a top view of a variation of an optical measurement system including a set of optical displacers configured to adjust respective trajectory lengths of a corresponding set of input light beams. Figure 42B and Figure 42C Shown Figure 42A Partial cross-sectional side view of the optical measurement system.

[0061] Figure 43A and Figure 43B Shown is a cross-sectional side view of a portion of a polarizing beam splitter with an immersed polarizer.

[0062] It should be understood that the proportions and sizes (relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, spacings and positional relationships presented therebetween are provided in the accompanying drawings solely to facilitate understanding of the various embodiments described herein and, therefore, may not necessarily be presented or illustrated to measure and are not intended to indicate any preference or requirement for the embodiments illustrated to exclude the embodiments described in conjunction therewith. DETAILED DESCRIPTION

[0063] Reference will now be made in detail to the representative embodiments illustrated in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to one preferred embodiment. On the contrary, it is intended to cover alternatives, modifications and equivalents that may be included within the spirit and scope of the described embodiments as defined by the appended claims.

[0064] The following disclosure relates to embodiments of an optical measurement system configured to perform spectroscopic measurements. The optical measurement system is configured to provide a compact arrangement for introducing light into a sample and collecting light returning from the sample. Reducing the size of the emission and / or collection architecture of the optical measurement system can make the entire optical measurement system smaller, thereby providing flexibility in integrating the optical measurement system into a variety of form factors.

[0065] To perform spectroscopic measurements on a sample, the optical measurement system can perform a measurement sequence of individual measurements. During each individual measurement, the optical measurement system can transmit input light (in the form of an emission beam, as described in greater detail herein) into a region of the sample and measure light returning from the sample to the optical measurement system (in the form of one or more return beams, as described in greater detail herein). The light measured during an individual measurement can represent the relative amount of input light returning to the optical measurement system. The optical measurement system can be configured such that the light measured during a given individual measurement can have certain additional properties, such as a specific distribution of optical path lengths and / or a specific distribution of sampling depths. This information can be used by the optical measurement system to determine one or more properties of the sample.

[0066] Because light of different wavelengths may interact differently with a given sample, it may be desirable for a measurement sequence to include multiple individual measurements performed at different wavelengths. In these cases, the input light may include light of different wavelengths during different individual measurements. In some cases, the optical measurement system may be configured to emit input light having a single wavelength for certain individual measurements. In this manner, a measurement sequence may include one or more individual measurements performed using a single wavelength (e.g., a first individual measurement using input light of a first wavelength, a second individual measurement using input light of a second wavelength, and so on). Additionally or alternatively, the optical measurement system may be configured to emit input light of multiple wavelengths for certain individual measurements. In these cases, a measurement sequence may include one or more individual measurements performed using multiple wavelengths (e.g., a first individual measurement using input light of a first plurality of wavelengths, a second individual measurement using input light of a second plurality of wavelengths, and so on). The wavelength (or wavelengths) associated with each individual measurement may be used by the optical measurement system to determine one or more properties of the sample.

[0067] In some cases, it may be desirable for an optical measurement system to be able to measure different regions of a sample without physically moving the optical measurement system relative to the sample. Thus, in some cases, the optical measurement systems described herein may include multiple measurement subsystems, such as those described in greater detail herein. In these cases, each measurement subsystem is capable of performing a separate measurement of a different, corresponding region of the sample. Specifically, each measurement subsystem is configured to, as part of a separate measurement, i) transmit an emission beam into the sample and ii) collect and measure a portion of the emission beam returning from the sample (e.g., using one or more detector elements). Depending on the configuration of the measurement subsystems and the choice of spectral measurement, separate measurements from different measurement subsystems may be performed simultaneously or sequentially.

[0068] In general, a measurement sequence will include a set of individual measurements performed at one or more regions of a sample using one or more wavelengths (collectively referred to as the "measurement wavelengths" for spectroscopic measurements). Collectively, these individual measurements can be analyzed to derive one or more properties of the sample (e.g., using spectroscopic analysis techniques). As one of ordinary skill in the art will readily appreciate, optical measurement systems can facilitate a wide range of analytical techniques.

[0069] The following references Figures 1A to 18C These and other embodiments are discussed. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for illustrative purposes only and should not be construed as limiting.

[0070] Generally, the optical measurement system described herein includes a light source unit configured to generate light to be used in spectral measurements; a transmission architecture configured to direct the generated light into a sample; a collection architecture configured to collect light returned from the sample; and one or more detector elements configured to measure the light collected by the collection architecture. The optical measurement system includes one or more transmission sites from which light is emitted. Each transmission site can emit a different corresponding light beam from the optical measurement system, and thus the optical measurement system can be configured to emit a single light beam or multiple light beams depending on the number of transmission sites. The transmission architecture routes the light generated by the light source unit to the one or more transmission sites and includes various components for generating the light beams emitted from the one or more transmission sites (as described in greater detail herein). The optical measurement system can be configured to control which transmission sites are emitting light at a given time, thereby providing the optical measurement system with additional flexibility when performing spectral measurements. For example, each transmit site may be associated with a different measurement subsystem of the optical measurement system (each optical measurement system may include corresponding transmit and collect architectures), and the optical measurement system may be able to control which measurement subsystems perform individual measurements at a given time.

[0071] The optical measurement system also includes one or more collection sites where light can enter the optical measurement system. Specifically, each collection site represents a different location where light can be collected from the sample. The collection architecture includes various components that collect light at the one or more collection sites (as will be described in more detail herein) and direct the collected light to one or more of the detector elements. Where the optical measurement system includes multiple measurement subsystems, each measurement subsystem may include a corresponding collection architecture. When light is introduced into the sample via the one or more transmission sites, a portion of the light may return to the optical measurement system after interacting with the sample (e.g., via reflection and / or scattering that may occur as the light passes through the sample). The proportion of light that returns to the optical measurement system may depend on the characteristics of the sample, and thus the amount of light collected by the collection sites of the optical measurement system may be measured and used to determine one or more sample properties.

[0072] Thus, each collection site can be associated with one or more detector elements that can be used to measure a corresponding portion of the light received by that collection site. In some variations, a collection site can be associated with multiple detector elements, in which case different portions of the light collected by the collection site are measured by different detector elements. Depending on the number of transmission sites, the number of collection sites, and the number of detector elements associated with each collection site, the optical measurement system can be capable of individually measuring different volumes of a given sample.

[0073] Each detector element is capable of outputting a signal based on the amount of light received by the detector element, which may depend at least in part on which (or which) transmitting sites are actively emitting light. Thus, the optical measurement systems described herein can be configured to perform separate measurements using one or more measurement channels. As used herein, a "measurement channel" refers to the path along which light is emitted from the optical measurement system, collected by the optical measurement system, and measured by the detector elements of the optical measurement system. A measurement channel comprises a detector element and one or more transmitting sites (including any additional components of the optical measurement system necessary to generate, emit, and collect the light, such as a light source unit, a transmitting architecture, and a collecting architecture) such that when the optical measurement system is used to measure a target sample (as described in more detail herein), each transmitting site of the measurement channel will simultaneously emit light, and at least a portion of the simultaneously emitted light will reach and be measured by the detector element. In these cases, the signal generated by the detector element represents the proportion of light emitted by the one or more transmitting sites that is collected from the sample and directed to the detector element.

[0074] An optical measurement system can be configured with a single measurement channel, or it can include multiple measurement channels. Where the optical measurement system includes multiple measurement channels, the optical measurement system can optionally utilize different measurement channels at different times. For example, the optical measurement system can include multiple measurement subsystems, each of which includes a corresponding set of measurement channels. In these cases, a first measurement subsystem can perform a first set of individual measurements using a first set of measurement channels during a first time period. During a second time period, a second measurement subsystem can perform a second set of individual measurements using a second set of measurement channels. The first set of individual measurements and the second set of individual measurements can be performed as part of a spectroscopic measurement as described herein. As used herein, unless otherwise specified, a "set" of a given element or component means a collection that includes at least one of that element or component. For example, a set of measurements can include a single measurement or multiple measurements.

[0075] The various embodiments described herein assume that each detector element is always part of the same corresponding measurement channel. In these cases, the optical measurement system is operated in such a way that each detector element will only measure light returned from a given emission beam. However, it will be understood that the optical measurement system can be such that a given detector element is positioned to selectively receive light from two or more transmission sites, if desired. The properties of the light measured by the detector element can vary depending on which transmission site is actively emitting light. For the purposes of performing spectral measurements, when a first transmission site is emitting light during a first individual measurement, the detector element can be considered to form a first measurement channel, and when a second transmission site is emitting light during a second individual measurement, the detector element can be considered to form a second measurement channel. Thus, the first individual measurement and the second individual measurement can be associated with different properties (e.g., different path length distributions and / or different depth sampling depth distributions).

[0076] While each detector element may be part of only a single measurement channel at a given time, a given transmission site may be part of multiple measurement channels simultaneously. For example, multiple detector elements may be capable of measuring different, corresponding portions of light emitted from a single transmission site. In these cases, each detector element may form a different measurement channel with at least a single transmission site. In general, while the principles described herein are discussed with respect to one or a few measurement channels, it should be understood that the optical measurement systems described herein can have several different measurement channels, if desired.

[0077] During a spectral measurement, different measurement channels can be used to perform separate measurements that together form a spectral measurement. Because each measurement channel represents a different combination of detector elements and transmission sites, each measurement channel will output a signal representing a measurement of a different area within the sample (although it will be understood that different measurement channels may measure partially overlapping sample volumes). In some cases, the output signals of multiple measurement channels may be combined together so that the output signals are combined into a single combined signal (e.g., a "combined output signal"). It will be understood that the output signals may be combined electrically (e.g., the electrical signals from multiple detector elements are combined so that a controller or processor that analyzes the output signals receives a single electrical signal) or may be combined digitally (e.g., a controller or processor that analyzes the outputs receives separate output signals and, for purposes of sample analysis, digitally combines them so that they are considered a single output signal). In general, the separate measurements from multiple channels may be combined or otherwise analyzed together to determine one or more sample properties of the sample being measured.

[0078] Typically, the design of an optical measurement system, as described herein, is tailored to perform spectroscopic measurements on samples having certain general sample properties. In these cases, the optical measurement system may only perform as expected if it is used to measure a sample having these general sample properties. For example, an optical measurement system designed to measure a solid sample may not operate as expected when used to measure a gas sample (or vice versa). Therefore, for ease of illustration, the design and performance of the optical measurement systems described herein are discussed with respect to a target sample. As used herein, a "target sample" refers to a theoretical sample on which the optical measurement system will perform spectroscopic measurements. The target sample has a set of predetermined target sample properties, including at least a target scattering coefficient (e.g., a target reduced scattering coefficient), a target absorption coefficient, and a target refractive index, which represent the sample that will actually be measured by the optical measurement system.

[0079] It should be understood that there may be additional sample properties (e.g., the concentration of one or more analytes) that may vary within the target sample while still satisfying the set of predetermined target sample characteristics. One or more of these sample properties may be measured by the optical measurement system as part of the spectroscopic measurement as described herein. Additionally, the target sample may have a complex structure in which the sample properties vary within the sample. For example, it may be assumed that the target sample comprises multiple layers, each of which has its own corresponding subset of target sample properties (e.g., a first layer may have a first target absorption coefficient, and a second layer may have a second target absorption coefficient). Thus, a given target sample property (such as a target absorption coefficient) may be defined by a single value representing the entire sample, or may be defined by multiple values, each representing a different corresponding portion of the target sample.

[0080] The optical measurement systems described herein can be designed and configured to operate in a specific manner when used to measure samples having target sample properties (target scattering coefficient, target absorption coefficient, etc.). For example, a measurement channel can be optimized to measure a specific sampling volume of a target sample, and when performing spectroscopic measurements on the target sample, the optical measurement system can assume certain operating characteristics (e.g., the distribution of optical path lengths of light measured by a given measurement channel and / or the distribution of sampling depths). If the actual sample measured by the optical measurement system has sample properties that significantly deviate from the sample properties of the target sample, the measurement channel may no longer operate as expected (e.g., a detector element of the measurement channel may no longer receive light during a measurement, the accuracy of the measurement performed by the measurement channel may be significantly affected, etc.).

[0081] However, it should be understood that, in practice, the actual sample measured by the optical measurement system may have one or more sample properties that differ from the sample properties of the target sample. If the sample properties of the measured actual sample are sufficiently close to the set of predetermined target sample properties (as determined by the accuracy constraints of the optical measurement system), the optical measurement system may still successfully perform spectral measurements on the actual sample. In other words, the optical measurement system may be optimized for the target sample but be used to perform spectral measurements on a variety of actual samples having different sample properties. In practice, it is likely that the optical measurement system will not actually be used to measure samples that actually meet all of the predetermined set of target sample properties.

[0082] For the purposes of this application, when specific principles of operation of an optical measurement system are discussed herein (such as the optical path length distribution and / or sampling depth distribution of light measured by a given measurement channel), it is assumed that these principles are discussed with respect to a target sample as defined herein. When the optical measurement system described herein is used to perform spectral measurements of an actual sample (referred to herein as a "measured sample"), the optical measurement system can analyze the individual measurements under the assumption that the sample properties of the measured sample are the same as the target sample properties. Alternatively, if one or more sample properties of the measured sample are known (e.g., predetermined or measured as part of the spectral measurement), the optical measurement system can use the known sample properties when analyzing the individual measurements.

[0083] Additionally, because one or more sampling characteristics of a sample can vary based on the wavelength of light emitted by the optical measurement system, it should be understood that the sampling characteristics of a target sample described herein are described with respect to a particular wavelength of light, referred to herein as the "target wavelength." Thus, when an optical measurement system is described herein as performing in a particular manner when measuring a target sample, it is assumed that the measurement is performed using input light having the target wavelength. The target wavelength can be one of the measurement wavelengths of a spectral measurement, such that at least one of the individual measurements performed by a measurement channel of the optical measurement system (e.g., using the target wavelength and / or other wavelengths sufficiently close to the target wavelength) can have a particular path length distribution and / or sampling depth distribution as described herein. Other individual measurements performed by the measurement channel using other wavelengths can have different path length distributions and / or sampling depth distributions, but can still provide useful information as part of the spectral measurement.

[0084] In some variations, it may be desirable to configure the optical measurement systems described herein to measure skin. For example, the optical measurement system may be positioned in contact with a user's skin such that light emitted from the optical measurement system enters the user's skin. Similarly, light may return to the optical measurement system after interacting with the user's skin and may be measured by one or more measurement channels of the optical measurement system. Thus, spectral measurements may be used to measure one or more properties of the user's skin.

[0085] When the optical measurement system is designed to use skin as a sample to be measured, a target sample representing the skin may be selected. The sampling characteristics of the skin may vary from user to user, so the optical measurement system may be designed based on the target sample representing the selected target skin sample. For example, for the target wavelengths described herein, the target skin sample may have a target refractive index between 1.3 and 1.5, a target finite element index between 0.5 mm and a target finite element index between 0.5 mm and 1.5 mm. -1 With 2mm -1 The target reduces the scattering coefficient and the value is between 0.5mm -1 With 4mm -1 In other cases, the optical measurement system may be designed to measure different types of samples, such as food, fluid, or gel solutions. In these cases, the optical measurement system may be designed based on a target sample representing the corresponding type of sample.

[0086] System Overview

[0087] Embodiments of the optical measurement systems described herein can be incorporated into a device having a housing. In some cases, the wearable device can operate solely to perform measurements using the optical measurement system, or can be a multifunctional device capable of performing additional functions, such as those readily understood by one of ordinary skill in the art. For example, in some cases, the optical measurement system can be incorporated into a smartphone, a tablet computing device, a laptop or desktop computer, a smartwatch, earphones, headphones, a head-mounted device, or other wearable device, or other electronic device (collectively referred to herein as an "electronic device" for ease of discussion).

[0088] The device may include a display (which may be a touch screen display) that provides a graphic output that can be viewed through the outer surface of the device or at the outer surface of the device. When the display is configured as a touch screen, the display may be able to receive touch input at the outer surface. The device may include a cover sheet (e.g., cover glass) located above the display, which forms at least a portion of the outer surface. The display can provide graphic output and, when configured as a touch screen, can receive touch input through the cover sheet. In some embodiments, the display includes one or more sensors (e.g., capacitive touch sensors, ultrasonic sensors, or other touch sensors) positioned above, below, or integrated with the display portion. In various embodiments, the graphic output of the display responds to the input provided to the electronic device. The portable electronic device may include additional components typical of a computing device, including a processing unit, a memory, an input device, an output device, additional sensors, etc.

[0089] Figure 1A and Figure 1B An example of an apparatus 100 housing an optical measurement system 102 as described herein is shown. Figure 1A A side view of a device 100 is shown, which includes, for example, a housing 104 having a top outer surface 106 (the housing 104 is Figure 1A 104 to illustrate a side view of components of optical measurement system 102 positioned within housing 104). This top exterior surface 106 defines a sampling interface 107 for optical measurement system 102, through which light generated by optical measurement system 102 can be emitted from optical measurement system 102 and device 100. Light can also pass through sampling interface 107 to re-enter optical measurement system 102 and device 100. While the same surface of device 100 serves as sampling interface 107 for both emitting and collecting light from the optical measurement system, it should be understood that sampling interface 107 can span multiple surfaces of device 100, such that light can be emitted and / or collected from different surfaces of device 100 (e.g., light is emitted from optical measurement system 102 at a portion of sampling interface 107 on a first surface of device 100, and light is collected by optical measurement system 102 at a second portion of sampling interface 107 on a second surface of device 100). Additionally or alternatively, light can be emitted from and / or collected from multiple different surfaces of device 100.

[0090] The sampling interface 107 includes at least one window that defines a set of transmitting sites 108a-108d of the optical measurement system 102 and a set of collecting sites 110a-110d of the optical measurement system 102. Figure 1A and Figure 1BIn the illustrated variation, the device comprises a plurality of transmitting sites 108a-108d and a plurality of collecting sites 110a-110d. Figure 1A and Figure 1B An equal number (e.g., four) of transmission sites 108a-108d and collection sites 110a-110d are depicted, but in other cases, the sampling interface 107 has an unequal number of transmission sites 108a-108d and collection sites 110a-110d. Each window defining a transmission site and / or collection site is transparent at any wavelength used by the measurement channel of the optical measurement system 102 associated with the transmission site and / or collection site. For example, during a spectral measurement, a given measurement channel will perform one or more separate measurements using a set of wavelengths (collectively referred to as the "measurement wavelengths" for that measurement channel, which may be some or all of the measurement wavelengths for the spectral measurements performed by the optical measurement system), as described in more detail herein. Thus, any window defining a transmission site may be transparent at the measurement wavelengths used for all measurement channels that include the transmission site. Similarly, any window defining a collection site may be transparent at the measurement wavelengths used for all measurement channels that include the collection site.

[0091] In some cases, each transmission site in the set of transmission sites 108a-108d and each collection site in the set of collection sites 110a-110d is defined by a different corresponding window. For example, the first transmission site 108a may be defined by a first window, the second transmission site may be defined by a second window, the first collection site 110a may be defined by a third window, the second collection site 110b may be defined by a fourth window, and so on. In these cases, the individual windows defining the individual transmission sites and collection sites may be separated from each other by one or more opaque portions of the housing (i.e., portions that absorb or otherwise block transmission of light at the measurement wavelength used by the optical measurement system 102). In other variations, some or all of the transmission sites 108a-108d and / or collection sites 110a-110d are defined in a common window (e.g., using a mask deposited on the window that is opaque at the measurement wavelength to define the apertures forming the individual transmission sites and / or collection sites). Additionally or alternatively, the apparatus 100 may include barriers, baffles, or other light-blocking structures (not shown) that may at least partially define some or all of the transmission sites 108 a-108 d and the collection sites 110 a-110 d. These light-blocking structures may block stray light and act as guides to limit the paths that light may take within the optical measurement system 102 before reaching a given transmission site or collection site at the sampling interface 107.

[0092] The optical measurement system 102 is capable of generating light during a spectral measurement and transmitting the light through the set of transmission sites 108a-108d. Specifically, the optical measurement system 102 may include a light source unit 140 configured to generate light within a wavelength range (including the measurement wavelengths used to perform individual spectral measurements). The light source unit 140 includes a set of light sources (not shown), each of which is selectively operable to emit light at a corresponding set of wavelengths. Each light source may be any component capable of generating light at one or more specific wavelengths, such as a light emitting diode or a laser. Lasers may include semiconductor lasers such as laser diodes (e.g., distributed Bragg reflector lasers, distributed feedback lasers, external cavity lasers), quantum cascade lasers, and the like. A given light source may be single-frequency (fixed wavelength) or tunable to selectively generate one of a plurality of wavelengths (i.e., the light source can be controlled to output different wavelengths at different times). The set of light sources may include any suitable combination of light sources and may operate collectively to generate light at any of a plurality of different wavelengths.

[0093] To the extent that the light source unit 140 is capable of generating multiple different wavelengths, the light source unit 140 can be configured to generate light of different wavelengths simultaneously and / or sequentially. Figure 1A and Figure 1B In the illustrated variation, the optical measurement system 102 includes a photonic integrated circuit 112. In these cases, the light source unit 140 may be integrated into the photonic integrated circuit 112, or may be separate from the photonic integrated circuit 112 and couple light into the photonic integrated circuit 112.

[0094] The photonic integrated circuit 112 routes the light generated by the light source unit 140 and emits the light from the photonic integrated circuit 112 to form one or more light beams. For example, the photonic integrated circuit 112 may include one or more output couplers (e.g., edge couplers, vertical output couplers, etc.) for emitting light from the photonic integrated circuit 112. The photonic integrated circuit 112 may be configured to emit a single light beam, or may be configured to emit multiple light beams. For example, where the sampling interface 107 includes a plurality of transmission sites 108a-108d, it may be desirable for the photonic integrated circuit 112 to emit a different light beam for each individual transmission site in the set of transmission sites 108a-108d (e.g., emitting a first light beam for the first transmission site 108a, emitting a second light beam for the second transmission site 108b, and so on). For example, where the optical measurement system 102 includes multiple measurement subsystems, different transmission sites 108a-108d may be associated with different measurement subsystems, which may allow the optical measurement system 102 to perform separate measurements at different locations on the sample being measured.

[0095] In some of these variations, the optical measurement system can individually control the timing and / or properties of some or all of the light beams emitted by the photonic integrated circuit 112. Specifically, in some cases, the emission of different light beams from the photonic integrated circuit 112 can be individually controlled. For example, the photonic integrated circuit 112 can be controlled to selectively emit a first set of light beams independently of a second set of light beams. Thus, at any given time, the optical measurement system 102 can control whether i) only the first set of light beams is emitted from the photonic integrated circuit 112 (and not the second set of light beams), ii) only the second set of light beams is emitted from the photonic integrated circuit 112 (and not the first set of light beams), or iii) if the photonic integrated circuit 112 is capable of emitting both sets of light beams simultaneously, the first set of light beams and the second set of light beams are emitted simultaneously by the photonic integrated circuit 112. Additionally or alternatively, the photonic integrated circuit 112 can be capable of generating light beams having different light properties (such as intensity, phase, and / or wavelength). In general, individual control of different light beams or different groups of light beams can reduce the amount of stray light lost within the optical system, can allow selective control of light emission through individual transmission sites 108a-108d (e.g., allowing some transmission sites to emit light while other transmission sites do not actively emit light), and / or can allow light properties (such as intensity, phase, or wavelength) to be selectively varied between different transmission sites 108a-108d.

[0096] It should be understood that in some variations, the optical measurement system 102 may include multiple photonic integrated circuits, each of which may include a different corresponding light source unit. In these cases, different photonic integrated circuits may be used to generate different light beams. Different photonic integrated circuits may be used to direct the light beams to different subsets of transmission sites 108a-108d (e.g., as part of different measurement subsystems or different groups of measurement subsystems), which may provide flexibility in routing the light beams to different transmission sites 108a-108d.

[0097] The optical measurement system 102 may include additional light-modifying components between the photonic integrated circuit 112 and the sampling interface 107. These light-modifying components collectively function to route light from the photonic integrated circuit 112 to the various transmission sites 108a-108d. For example, these light-modifying components may be used to redirect, combine (e.g., such that multiple light beams emitted from the photonic integrated circuit 112 are combined into a single light beam), separate (e.g., such that a single light beam is separated into multiple separate light beams), reshape, or otherwise modify the light beams emitted from the photonic integrated circuit 112, or change the divergence of these light beams. Examples of light-modifying components include lenses (which change the divergence and / or direction of the light beams), diffusers, mirrors, beam splitters, polarizers, and the like. For purposes of illustration, a first set of optical components is schematically depicted as a block 114 positioned between the photonic integrated circuit 112 and the sampling interface 107. It should be understood that, in some cases, the sampling interface 107 itself may function as a light-modifying component (e.g., it may have an integrated lens capable of changing the divergence and / or direction of light passing therethrough, etc.). Together, the photonic integrated circuit 112, the sampling interface 107, and any intervening light-modifying components 114 may form a transmit architecture for the optical measurement system 102 and cooperate to determine characteristics of light emitted from each of the transmit sites 108a-108d. Examples of different transmit architectures are described in more detail herein.

[0098] The optical measurement system also includes one or more detector groups 116a-116d, each of which includes a corresponding set of detector elements. Each of the one or more detector groups 116a-116d is positioned within the device 100 to receive light that has entered the device 100 (and thereby entered the optical measurement system 102) through the sampling interface 107 (e.g., via one or more collection sites in the set of collection sites 110a-110d). Each of the one or more detector groups 116a-116d includes one or more detector elements configured to measure light received by the optical measurement system 102 (e.g., light that has been emitted from the optical measurement system toward the sample being measured and returned to the optical measurement system) during a measurement. Each detector element is capable of generating an output signal representative of the amount of light measured by the detector element (and thus forming an output signal of a measurement channel as described herein). Thus, a detector group including multiple detector elements can generate multiple corresponding output signals.

[0099] It should be understood that in some cases, the outputs of two or more detector elements may be combined such that the signals generated by the two or more detector elements are combined into a single output signal, such as described in more detail herein. In general, the light measured by the set of detector elements during a measurement sequence of separate measurements can be analyzed to determine one or more properties of the sample being measured. Light can be measured by a given detector element (or combined group of detector elements) when the corresponding transmission site (including one or more transmission sites 108) is emitting light, which can be indicative of how the emitted light interacts with the sample. Optionally, light can also be measured when the corresponding emission site is not actively emitting light, which can measure background light incident on the detector element and / or dark current for background correction operations.

[0100] In some variations, the optical measurement system 102 includes one or more light modifying components positioned between the sampling interface 107 and one or more of the detector groups 116a-116d. These light modifying components are used collectively to route light from the various collection sites 110a-110d to the detector groups 116a-116d. For example, these light modifying components can be used to redirect, combine (e.g., such that multiple light beams collected by one or more collection sites 110a-110d are combined into a single light beam), separate (e.g., such that a single light beam is separated into multiple individual light beams), reshape, otherwise modify the light beams collected by the group of collection sites 110a-110d, or change the divergence of these light beams. Examples of light modifying components include lenses (which change the divergence and / or direction of the light beams), diffusers, mirrors, beam splitters, polarizers, etc. For illustrative purposes, the second set of optical components is shown in FIG. Figure 1A Schematically depicted in FIG. 1 as a box 118 positioned between the sampling interface 107 and one or more detector groups 116a - 116d .

[0101] For each collection site in the set of collection sites 110a-110d, the light-modifying component 118 can control how light entering the optical measurement system 102 via the collection site is routed to one or more detector elements of the detector groups 116a-116d. For example, if light entering the first collection site 110a has a first set of characteristics (e.g., enters the optical measurement system 102 at a specific location at the first collection site 110a at a specific angle of incidence), the light can be routed to a first detector element (e.g., a first detector element of the first detector group 116a) by the light-modifying component 118. If light entering the first collection site 110a has a different second set of characteristics (e.g., enters at a different location and angle of incidence), the light can be routed to a second detector element (e.g., a second detector element of the first detector group 116a). Together, the one or more detector groups 116a-116d, the sampling interface 107, and any intervening light-modifying components 118 can form one or more collection architectures of the optical measurement system 102 and cooperate to determine characteristics of light collected by each of the collection sites 110a-110d and measured by the one or more detector groups 116a-116d. Examples of different collection architectures are described in more detail herein.

[0102] In some cases where the optical measurement system 102 includes the photonic integrated circuit 112, the photonic integrated circuit 112 and one or more of the detector groups 116a-116d are mounted to a common component. Figure 1A and Figure 1B In the illustrated variations, the optical measurement system 102 includes an interposer 120. In these cases, the photonic integrated circuit 112 and one or more detector groups 116a-116d are all mounted on the interposer 120, which in turn can serve as an electrical interface for these components (e.g., routing power, control, and / or other signals to and from these components). In some cases, the interposer also serves as a heat sink. In variations where the optical measurement system 102 includes multiple photonic integrated circuits, some or all of the photonic integrated circuits may be mounted on the interposer 120. In other variations, the photonic integrated circuit 112 is mounted to a component separate from some or all of the detector groups 116a-116d. In other variations, some or all of the detector groups 116a-116d are directly mounted on (or otherwise integrated into) a portion of the photonic integrated circuit 112.

[0103] exist Figure 1AController 160 is also shown. Controller 160 is configured to control the operation of optical measurement system 102 to perform spectral measurements. Specifically, controller 160 is operably connected to various components of the optical measurement to control the operation of these components. For example, controller 160 can be operably connected to light source unit 140 and can control light source unit 140 to generate one or more wavelengths of light as needed during spectral measurement. Similarly, controller 160 can be operably connected to one or more detector groups 116a-116d to receive output signals generated by each detector element. In fact, controller 160 can control the operation of any active component (e.g., controllable phase shifters, optical switches, moving parts) during spectral measurement. In addition, controller 160 can be configured to process the output signals received during spectral measurement to determine one or more sample properties of the sample being measured.

[0104] Controller 160 may include any suitable combination of hardware, software, and / or firmware necessary to control the various operations of optical measurement system 102. For example, controller 160 may include one or more processors and memory. The memory may include one or more non-transitory computer-readable storage media for storing computer-executable instructions that, when executed by one or more computer processors, may cause the computer processors to perform the techniques described herein (e.g., controlling individual components of optical measurement system 102 to perform spectroscopic measurements). A computer-readable storage medium may be any medium that can tangibly contain or store computer-executable instructions for use by or in conjunction with an instruction execution system, apparatus, or device. In some examples, the storage medium is a transient computer-readable storage medium. In some examples, the storage medium is a non-transitory computer-readable storage medium. Non-transitory computer-readable storage media may include, but are not limited to, magnetic storage devices, optical storage devices, and / or semiconductor storage devices. Examples of such storage devices include magnetic disks, optical disks, and persistent solid-state memory such as flash memory and solid-state drives.

[0105] Similarly, the one or more processors may include, for example, dedicated hardware as defined herein, a computing device as defined herein, a processor, a microprocessor, a programmable logic array (PLA), a programmable array logic (PAL), a general array logic (GAL), a complex programmable logic device (CPLD), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or any other programmable logic device (PLD) that may be configured to execute an operating system and operations of the optical measurement system 102. The specific details and arrangement of the controller 160 that may control the various operations of the optical measurement system 102 will be readily understood by those of ordinary skill in the art and, therefore, will not be described in further detail herein.

[0106] The optical measurement system described herein (such as Figure 1A and Figure 1B The optical measurement system 102 may perform spectral measurements on a sample to determine one or more sample properties of the sample being measured. The optical measurement system may utilize one or more measurement channels to perform a measurement sequence comprising a set of individual measurements. Specifically, each individual measurement represents a measurement performed by a particular measurement channel over a sampling duration and using light of a particular wavelength or wavelengths. A spectral measurement may include multiple individual measurements performed sequentially (e.g., at different corresponding wavelengths) by the same measurement channel. Additionally or alternatively, a spectral measurement may include individual measurements performed by multiple measurement channels (i.e., each of the multiple measurement channels performs one or more corresponding individual measurements). Individual measurements from different measurement channels may be performed simultaneously (e.g., during the same sampling period or during partially overlapping sampling periods) or sequentially as desired. Collectively, a spectral measurement may include multiple individual measurements performed over a wavelength range (i.e., the measurement wavelength of the spectral measurement), which may be combined or analyzed together to determine one or more sample properties of the sample being measured.

[0107] During each individual measurement, the optical measurement system emits light and measures the light returned to the optical measurement system for a given measurement channel. The relative amount of light returned for a given individual measurement can depend on the sample being measured and, therefore, can provide information about one or more properties of the sample. Specifically, a portion of the light introduced into the sample can be absorbed as it travels through the sample. The amount of light absorbed depends, at least in part, on the contents of the sample (e.g., the presence and concentration of different substances within the sample) and the optical path length of the light (i.e., the length traveled by the light within the sample). Therefore, it may be desirable to understand and control the path length of light measured by individual measurement channels of the optical measurement systems described herein.

[0108] For example, an optical measurement system can be configured to measure a volumetric scattering sample, such as skin. In these cases, the transmission and collection sites associated with a given measurement channel can be positioned so that light introduced into the sample will scatter within the sample before returning to the optical measurement system. Individual photons can scatter differently within the volumetric scattering sample, and thus each photon measured by the measurement channel can travel a different corresponding path (having a corresponding path length) through the sample. Consequently, each measurement channel can be associated with a corresponding "path length distribution," which represents a probability distribution representing the likelihood that a photon of light measured by the measurement channel (i.e., light introduced into the sample from the optical measurement system and collected by the measurement channel's detector elements) will have a particular optical path length for a sample having certain properties (e.g., a target sample, as described herein). It should be understood that the path length distribution of light measured by a measurement channel can vary based on the sample characteristics of the sample being measured. A separate measurement performed on a target sample can have a specific path length distribution for a given measurement channel, and this path length distribution can change as the measurement channel is used to measure a different sample being measured (e.g., a sample having sampling characteristics different from the target sample characteristics).

[0109] The characteristics of the path length distribution of a given measurement channel can affect the accuracy of individual measurements performed by the measurement channel. Wide variations in the range of measured optical path lengths can make it more difficult to accurately measure certain sample properties (e.g., the presence and / or concentration of a particular substance within a sample). For example, a narrower distribution (i.e., having less scatter) can provide a higher degree of confidence that the light measured by the measurement channel has a particular optical path length. Therefore, it may be desirable to design one or more measurement channels of an optical measurement system to provide a narrow path length distribution for measurements performed on a target sample (e.g., using a target wavelength as described herein).

[0110] Figures 2A to 2C illustrates how the design of a measurement channel can affect the path length distribution of measurements performed by the measurement channel. Figure 2A An example of a measurement channel of the first optical measurement system 200 is shown. The first optical measurement system 200 can be as described above with respect to Figure 1A and Figure 1B Specifically, the first optical measurement system 200 includes a transmitting architecture (schematically depicted as box 202 ), a collecting architecture (schematically depicted as box 204 ), and a sampling interface 207 defining a transmitting site 208 and a collecting site 210 .

[0111] The transmission architecture 202 is configured to generate an emission light beam 212 that exits the sampling interface 207 at a transmission site 208. Similarly, the collection architecture 204 is configured to collect a return light beam 214 that passes through the collection site 210 and direct the return light beam 214 to a detector element (not shown) of the measurement channel. It should be understood that the collection site 210 may receive additional light in addition to the return light beam 214, but this light is not transmitted by the detector element 214. Figure 2A In some cases, some of this light may be measured by other measurement channels of first optical measurement system 200 .

[0112] The emitted light beam 212 may have certain beam properties when it leaves the transmission site 208, including beam size (i.e., the size of the light beam when it leaves the transmission site 208), beam shape (i.e., the shape of the light beam when it leaves the transmission site 208), and beam vergence (e.g., the amount of divergence of the light beam when it leaves the transmission site 208). Figure 2A When a target sample 240 (as shown) is placed against the sampling interface 207, the emitted light beam 212 will have these beam properties when it enters the sample. Similarly, the return light beam 214 will also have a set of beam properties (i.e., beam size, beam shape, and beam vergence) when it leaves the sample and enters the collection site 210. Because the beam vergence of a light beam depends on the refractive index of the medium carrying the light beam, the actual beam vergence of the emitted light beam 212 when it leaves the transmission site 208 depends on what is positioned against the transmission site 208 when the emitted light beam leaves the transmission site 208. Therefore, when values ​​of beam vergence are used to characterize a light beam as described herein, unless otherwise specified, these values ​​reflect the beam vergence of the light beam as measured in air (e.g., a refractive index of 1).

[0113] Together, the beam properties of the emitted light beam 212 and the returned light beam 214 may at least partially determine the path length distribution (for a given sample) of the light measured by the measurement channel. Figure 2A As shown, when the first optical measurement system 200 is used to measure a target sample 240, the emitted light beam 212 will penetrate into the target sample 240 upon exiting the sampling interface 207. As the light interacts with the target sample 240, at least a portion of the light will return to the sampling interface 207 (e.g., via scattering) at a set of ray positions / angles that define a return light beam 214. The amount of light that returns to the optical measurement system 200 as the return light beam 214 depends, at least in part, on target sample characteristics (e.g., a target scattering coefficient, a target absorption coefficient, and a target refractive index).

[0114] While individual photons may take different paths through the target sample 240, the light measured by the detector elements (i.e., the collected return beam 214) as a whole will primarily travel through a particular volume of the target sample 240. For example, Figure 2A Including for Figure 2A A sampling volume 216 of possible optical paths for a measurement channel is shown. Specifically, sampling volume 216 represents the possible area of ​​a sample that can be measured by the measurement channel (i.e., by photons in emission beam 212 that are returned to first optical measurement system 200 as part of return beam 214) with a minimum threshold probability. In other words, it is possible for a single photon measured by a measurement channel to travel outside of sampling volume 216, but the probability of this occurring is less than the minimum threshold probability.

[0115] A single photon can take a range of different possible optical paths within the target sample 240, and for a given photon, each possible optical path has a corresponding probability. Collectively, it is more likely that a photon will follow an optical path with a given optical path length (or a range of optical path lengths). For example, Figure 2C A plot 230 of probability as a function of optical path length is shown, which represents the relative probability that a photon of light collected by a measurement channel will traverse a particular optical path length. Specifically, the plot 230 includes Figure 2A Path length distribution 232 of the measurement channels of the first optical measurement system 200 is shown in FIG. Figure 2A The measurement channel shown in FIG2 is configured to generate collimated emission beams 212 and collect collimated return beams 214, each of which has a relatively narrow beamwidth. Consequently, the path length distribution 232 for this measurement channel has a relatively narrow distribution around a median path length 236. As used herein, the "median path length" of a path length distribution refers to the path length representing the 50% value of the cumulative distribution function based on the path length distribution. In other words, there is a 50% probability that a given photon measured by the measurement channel will travel an optical path length in the sample that is shorter than the median path length.

[0116] on the contrary, Figure 2B 2 shows a measurement channel of a variation of the second optical measurement system 220. The second optical measurement system 220 can be configured identically to the first optical measurement system 200 (e.g., having the same sampling interface 207 and collection architecture 204), except that the second optical measurement system 220 includes a sensor configured to generate a signal having a ratio of 0.01 to 0.01. Figure 2A The collimated transmission beam 212 generated by the transmission architecture 202 (for comparison, Figure 2BBy increasing the beam width of the collimated emission beam 224, the measurement channel of the second optical system 220 will measure a larger sample volume 216 (in the example shown in dashed lines) than the measurement channel of the first optical measurement system 200. Figure 2B A larger sampling volume 226 (with the same minimum threshold probability) is shown for comparison. Figure 2C , the measurement channel of the second optical measurement system 220 has a second, wider path length distribution 234, even though the path length distributions 232, 234 may have the same median path length 236. Similarly, changing the beam vergence of the emission and / or collection beams of a measurement channel (e.g., increasing the divergence) may increase the measurement volume but may negatively impact the path length distribution of the measurement channel.

[0117] Optical measurement system with increased volume sampling

[0118] For many optical measurement systems, there is a tradeoff between the sample volume measured by a measurement channel and the shape of the path length distribution of that measurement channel. A narrower path length distribution provides a better understanding of the optical path length of the measured light, which can improve the accuracy of spectral measurements. On the other hand, a larger sample volume can make the optical measurement system less susceptible to local heterogeneity in the measured sample and / or coherent noise associated with the sample volume. Therefore, it may be desirable to provide an optical measurement system with one or more measurement channels designed to measure a larger sample volume while still maintaining a narrow path length distribution.

[0119] Specifically, in some variations of the optical measurement systems described herein, the optical measurement systems are configured to transmit a converging emission beam into a sample being measured. Depending on the configuration of the optical measurement system, such as will be described in greater detail herein, the converging emission beam can increase the sampling volume of the target sample for one or more measurement channels without significantly changing the path length distribution of those measurement channels.

[0120] Figure 3A A partial cross-sectional side view of a device incorporating an optical measurement system 300 as described herein is shown. The optical measurement system 300 includes a sampling interface 307 having a transmission site 308 (as described in more detail herein) and a transmission architecture 302. The transmission architecture 302 is configured to generate and transmit a transmission beam 304 that exits the sampling interface 307 through the transmission site. While the sampling interface 307 is Figure 3A 304. The sampling interface 307 is not depicted as part of the transmit architecture 302, but it will be appreciated that in some variations the sampling interface 307 may be configured to shape or otherwise steer the transmit beam 304 (and thus may be part of the transmit architecture).

[0121] The emitted light beam 304 has certain beam properties as it leaves the sampling interface 307, including a beam width W along a first dimension. E and beam divergence half angle θ E (For example, along the use Figure 3A The beam width W is the XZ plane of the Cartesian coordinate system depicted in . E represents the size of the emitted beam 304 along the first dimension as it exits the optical measurement system 300 and enters a sample (not shown) positioned in contact with the sampling interface 307. Similarly, the beam divergence half angle θ E represents the half angle at which the emission light beam 304 converges along the first dimension as it leaves the optical measurement system 300 and enters the sample. Figure 3A 308, but it will be appreciated that the beam vergence of the transmitted light beam 304 may have different values ​​as it passes through different materials. For example, the transmission site 308 may be formed of a material (e.g., sapphire crystal, glass, etc.), and the transmitted light beam 304 may have a different beam vergence when passing through the material than when passing through different media on either side of the transmission site 308 (e.g., air present against the inside of the transmission site 308 and / or a sample positioned against the outside of the transmission site 308).

[0122] Although the emission light beam 304 is shown as passing through the transmission site 308 at normal incidence (e.g., the beam direction 334 of the emission light beam 304 is perpendicular to the outer surface of the transmission site 308), it should be understood that in some cases, the emission light beam 304 may pass through the transmission site 308 at non-normal incidence (e.g., the beam direction 334 of the emission light beam 304 is positioned at a non-perpendicular angle relative to the outer surface of the transmission site 308).

[0123] When a sample is placed against transmission site 308, emission beam 304 projects a projected emission beam 306 into the sample. Projected emission beam 306 represents the path that emission beam 304 would take through the sample if no scattering occurred within the sample. In other words, projected emission beam 306 represents the initial trajectory of the photons of emission beam 304 upon entering the sample. Thus, while the actual photons of emission beam 304 may undergo one or more scattering events after entering the sample, projected emission beam 306 can be useful in understanding emission beam 304 upon exiting optical measurement system 300.

[0124] Specifically, the emission beam 304 can be configured to project the projected emission beam 306 into a transition region 310 in the target sample. The transition region 310 represents the location where the projected emission beam 306 transitions along a first dimension from a converging beam (as shown by the converging portion 306a of the projected emission beam 306) to a diverging beam (as shown by the diverging portion 306b of the projected emission beam 306).

[0125] The projected transmit beam 306 will have a beam width W along the first dimension at the transition region 310. S and beam divergence half angle θ S In addition, the transition region 310 will be located at a depth d in the target sample. S It should be understood that the beam width W S and beam divergence half angle θ S and depth d S The optical beam width W may depend on the beam characteristics of the emission beam 304 (e.g., the beam width W E , beam divergence half angle θ E and beam direction 334) and certain sample properties of the target sample (e.g., refractive index). For example, a change in the refractive index at the interface between the transmission site 308 and the sample may cause the transmitted beam 304 to refract upon entering the sample. Although the transition region 310 is Figure 3A 304 as being parallel to the outer surface of the sampling interface 307, but it should be understood that in other cases, the transition region 310 may be at a non-zero angle relative to the sampling interface 307 depending on the properties of the emission beam 304.

[0126] Increase the beam divergence half angle θ of the transmitted light beam 304 E and / or beamwidth W E The etendue of the emission beam 304 (and thereby the etendue of the projected emission beam 306) may be increased, which may increase the sample volume measured by one or more measurement channels of the optical measurement system 300. For example, in some variations, the optical measurement system 300 is configured to emit a beam having a beam divergence half-angle θ of at least 5 degrees along a first dimension when the emission beam 304 leaves the transmission location 308. E In some of these variations, when the emission beam 304 leaves the transmission site 308, the convergent emission beam has a beam divergence half-angle θ of at least fifteen degrees measured in air along the first dimension. E .

[0127] Similarly, in some variations, the optical measurement system 300 is configured to emit an emission beam 304 that projects a projected emission beam 306 into a target sample (such as discussed in more detail herein), wherein the projected emission beam 306 has a beam divergence half-angle θ of at least three degrees measured in the target sample along a first dimension at a transition region 310. S In other words, at any given point along the transition region 310, the transition region 310 is projected to receive projected rays of the projected emission beam 306 that span at least six degrees (e.g., ± three degrees around a center ray projected to pass through that point), as measured in the target sample. In some of these variations, the beam vergence θ S At least ten degrees along the first dimension, as measured in the target sample.

[0128] It should be understood that the emission beam 304 and the projected emission beam 306 may have different beam properties in other dimensions. For example, Figure 3B Shown Figure 3A For illustration, the sampling interface 307 is not shown in FIG. Figure 3B , and line 338 represents the point at which the emission beam 304 leaves the sampling interface. As shown, when the emission beam 304 leaves the sampling interface, the emission beam 304 may have a first beam width W in the first dimension. E (For example, in Figure 3B ), and when the emission beam 304 leaves the sampling interface, the emission beam may have a second beam width W in a second dimension perpendicular to the first dimension. L (For example, in Figure 3B In some variations, the second beam width W L Greater than the first beam width W E In some of these variations, the second beamwidth W L is the first beam width W E In some of these variations, the second beam width W L is the first beam width W E As a result, the projected emission beam 306 can also be projected to have a beam width W in the second dimension that is greater than that in the first dimension. S Large second beamwidth W T .

[0129] Similarly, the beam vergence of the transmitted light beam 304 along the first dimension (eg, the beam vergence half angle θ E) may be different from the beam vergence along the second dimension. For example, while the emission beam 304 (and thus the projected emission beam 306) may be converging in the first dimension, the emission beam 304 may be collimated in the second dimension. Optionally, the emission beam 304 may be diverging in the second dimension. In other variations, the emission beam 304 may be configured to converge in the second dimension. In these cases, the beam vergence of the emission beam 304 in the second dimension may be the same as or different from the beam vergence in the first dimension.

[0130] The properties of emission beam 304 and projected emission beam 306 can affect the accuracy of measurements made by optical measurement system 300. For example, the optical measurement systems described herein can emit an emission beam that is configured such that, when the emission beam is introduced into a target sample, a transition region is positioned at an angle-independent sample region for at least one measurement channel. As used herein, a sample region is considered "angle-independent" for a given measurement channel if the path length distribution of light projected through the sample region is independent of the angle at which the light is projected through the sample region.

[0131] Figures 4A to 4F The concept of angle-independent sample area is shown. Figure 4A and Figure 4B A partial cross-sectional view of an optical measurement system 400 for measuring a target sample 402 using light of a target wavelength is shown. Specifically, the optical measurement system 400 includes a collection architecture (schematically depicted as box 404) and a sampling interface 407 defining a transmission site 408 and a collection site 410, such as described herein. The optical measurement system 400 includes a first measurement channel, and the collection architecture 404 is configured to collect a return beam 414 from the target sample 402 through the collection site 410 and direct the return beam 414 to a detector element (not shown) of the first measurement channel.

[0132] Figure 4A Also shown in FIG is a first sample region 440 which is angle-independent for the first measurement channel. Figure 4A 4. FIG. 4 shows two example light rays, a first light ray 411a and a second light ray 411b. Both first light ray 411a and second light ray 411b are projected as part of an emission beam through first sample region 440. Specifically, first light ray 411a has a first projected light ray 412a, which represents the projection path of first light ray 411a in target sample 402 if no scattering occurs. Similarly, second light ray 411b has a second projected light ray 412b. First projected light ray 412a and second projected light ray 412b each intersect first sample region 440.

[0133] If light is introduced into target sample 402 along the trajectory of first ray 411a and second ray 411b, individual photons will be scattered within target sample 402 before being collected as part of return beam 414, as described herein. Figure 4B A first sampling volume 416a of a possible optical path of a first measurement channel originating from the trajectory of a first ray 411a and a second sampling volume 416b of a possible optical path of a first measurement channel originating from the trajectory of a second ray 411b are shown. Thus, photons entering the target sample 402 along the trajectory of the first ray 411a may sample a different (but partially overlapping) volume of the target sample 402 than photons entering the target sample 402 along the trajectory of the second ray 411b.

[0134] Even though the light traveling along the trajectories of the first ray 411a and the second ray 411b samples different sampling volumes 416a, 416b, the light will have approximately the same path length distribution. Figure 4C A plot 430 of probability as a function of optical path length is shown. Specifically, plot 430 includes a first path length distribution 432 and a second path length distribution 434 for a first measurement channel of optical measurement system 400. First path length distribution 432 represents the path length distribution of light that enters target sample 402 along the trajectory of first ray 411 a and is collected as part of return beam 414 (e.g., measured by the first measurement channel). Second path length distribution 434 represents the path length distribution of light that enters target sample 402 along the trajectory of second ray 411 b and is measured by the first measurement channel.

[0135] First path length distribution 432 is substantially identical to second path length distribution 434. For purposes of this application, multiple path length distributions (each associated with a corresponding median path length) are considered "approximately identical" if their median path lengths are all within 10% (e.g., ±10%) of the average of the median path lengths. Similarly, additional light rays (not shown) projected through first sample area 440 from other angles may also have corresponding path length distributions that are approximately identical to first path length distribution 432 and second path length distribution 434. Therefore, if these different light rays are combined into a light beam, the overall path length distribution of the light beam will be approximately identical to the individual path length distributions associated with each ray. In this way, the light projected to travel through first sample area 440 is independent of the angle at which the light is projected to travel through the sample, and first sample area 440 is considered an angle-independent sample area for measuring a channel.

[0136] It will be appreciated that other regions of the target sample 402 will not be angle independent for the first measurement channel. Figure 4D and4E Also depicted Figure 4A and Figure 4B Partial cross-sectional side view of the optical measurement system 400 and highlighting the second sample region 442 that is not angle-independent for the first measurement channel. Figure 4D and Figure 4E 4. Two example light rays, third light ray 421a and fourth light ray 421b, are depicted as being projected to pass through second sample region 442 (e.g., respective third and fourth projected light rays 422a, 422b intersect second sample region 442). If light is introduced into target sample 402 along the trajectories of third light ray 421a and fourth light ray 421b, the single photon will be scattered within target sample 402 as described herein before being collected as part of return beam 414. Figure 4E A third sampling volume 426a of a possible optical path of the first measurement channel originating from the trajectory of the third ray 421a and a fourth sampling volume 426b of a possible optical path of the first measurement channel originating from the trajectory of the fourth ray 421b are shown.

[0137] The light sampled from the third sampling volume 426a and the fourth sampling volume 426b will have different path length distributions. Figure 4F A plot 450 of probability as a function of optical path length is shown. Specifically, plot 450 includes a third path length distribution 452 and a fourth path length distribution 454 for the first measurement channel of optical measurement system 400. Third path length distribution 452 represents the path length distribution of light that enters target sample 402 along the trajectory of third ray 421 a and is measured by the first measurement channel. Fourth path length distribution 454 represents the path length distribution of light that enters target sample 402 along the trajectory of fourth ray 421 b and is measured by the first measurement channel.

[0138] The third path length distribution 452 differs from the fourth path length distribution 454 in one or more aspects. Figure 4FAs shown, third path length distribution 452 and fourth path length distribution 454 have sufficiently different median path lengths that third and fourth path length distributions 452, 454 are not approximately identical. If light is introduced simultaneously along the trajectories of third and fourth light rays 421a, 421b, the total path length distribution 456 of the light measured by the first measurement channel will be a combination of third path length distribution 452 and fourth path length distribution 454, which can significantly expand the total path length distribution compared to either third or fourth path length distributions 452, 454. Introducing light along additional trajectories projected through second sample region 442 will further expand the shape of total path length distribution 456. Because different rays of the emitted light beam are associated with different path length distributions, second sample region 442 is an angularly dependent sample region 442.

[0139] Return to Figure 3A and Figure 3B If the transition region 310 is positioned at an angularly independent region of the target sample for a given measurement channel, the entire emission beam 304 is projected to intersect the angularly independent region of the target sample. Specifically, the path length distribution of the individual rays forming the emission beam 304 (e.g., the beam divergence half angle θ across the emission beam 304) is E and the beam divergence half angle θ of the projected emission beam 306 S ) will have approximately the same path length distribution for the target wavelength. As a result, the beam divergence half angle θ of the transmitted light beam 304 can be increased E , to increase the total volume of the target sample measured by a measurement channel without significantly changing the path length distribution of the light measured by the measurement channel.

[0140] In these cases, it may be desirable to configure the transmit beam 304 to have a relatively large beam divergence half-angle θ E To generate such a transmit beam 304 while maintaining a compact form factor, the transmit architecture 302 may include a beamformer 320 and a transmit optical subassembly 324 including one or more lens elements. The beamformer 320 is configured to generate an output beam 326 that diverges in at least one dimension (e.g., at least a first dimension). For example, Figure 3A As shown in FIG, the output beam 326 has a beam width W in the first dimension. D And in the first dimension, the beam divergence half angle θ O Divergence. The output beam 326 can be divergent, convergent, or collimated as desired (and depending on the configuration of the beamformer 320).

[0141] The transmit optics subassembly 324 is configured to receive and shape the output beam 326 to form the transmit beam 304. Figure 3A and Figure 3B 304 is shown as being formed by a single cylindrical lens, but it should be understood that the transmit optics subassembly 324 may include any suitable number or combination of lens elements as desired to form the transmit beam 304 from the output beam 326. Thus, the beam divergence half-angle θ of the output beam 326 along the first dimension is E The beam divergence half angle θ of the transmitted light beam 304 O The relationship between and may depend on the optical magnification of the transmit optical subassembly 324 in the first dimension. For example, if the optical subassembly 324 provides 1x optical magnification in the first dimension, the beam divergence half-angle θ of the output light beam 326 is E The beam divergence half angle θ of the transmitted light beam 304 may be O Examples of the beamformer 320 and transmit optics subassembly 324 are described in greater detail herein.

[0142] In some variations, the optical measurement systems described herein may be configured to collect and measure, for at least one measurement channel, a return light beam that is projected to intersect an angularly independent sample region. Figure 5A A partial cross-sectional side view of a portion of one such variation of an optical measurement system 500 as described herein is shown. The optical measurement system 500 includes a sampling interface 507 and a collection architecture 502 having a collection site 510 as described in more detail herein. The collection architecture 502 is configured to collect one or more return beams that enter the sampling interface 507 through the collection site 510 and is further configured to direct each return beam to a corresponding detector element. While the sampling interface 507 is Figure 5A 502, but it will be appreciated that in some embodiments the sampling interface 507 may be configured to shape or otherwise redirect the return beam (or beams) collected from the collection location 510 (and thus may be part of the collection architecture).

[0143] Figure 5A A first return beam 504 is depicted that is collected by the collection architecture 502 when the transmitting architecture (not shown) of the optical measurement system 500 transmits one or more transmit beams into a measurement sample (not shown). Figure 5AIn the variation shown, the collection architecture 502 also includes a collection optics subassembly 524 and a first detector element 520. The collection optics subassembly 524 includes one or more lens elements and is configured to receive the first return beam 504 and shape it to form a first measurement beam 526. The collection optics subassembly 524 is also configured to direct the first measurement beam 526 to the first detector element 520. In other words, the first return beam 504 defines a first set of position and angle pairs on the collection site 510. Any light that enters the optical measurement system 500 through the collection site 510 at a position / angle pair associated with the first return beam 504 will be directed (e.g., via the collection optics subassembly 524 and the first measurement beam 526) to and measured by the first detector element 520, which is part of the first measurement channel of the optical measurement system 500. Although the collection optics subassembly 524 is Figure 5A and Figure 5B 526 from the first return beam 504. In the embodiment shown in FIG. 526 , the collection optics subassembly 524 is shown as being formed by a single cylindrical lens, but it should be understood that the collection optics subassembly 524 can include any suitable number or combination of lens elements as desired to form the first measurement beam 526 from the first return beam 504. Furthermore, while the collection optics subassembly 524 is shown as having positive magnification, it should be understood that the collection optics subassembly 524 can be configured to have negative magnification, which in some cases can allow the collection optics subassembly 524 to be configured with fewer lenses.

[0144] In some variations, the first return beam 504 is directed along a first dimension (e.g., along a plane using Figure 5A Specifically, the collection architecture 502 can be configured such that the first return beam 504 has certain beam properties upon entering the sampling interface 507, including a beam width W along a first dimension. R and beam divergence half angle θ R . Beam width W R represents the size of the first return beam 504 along the first dimension as it leaves the sample (not shown) positioned in contact with the sampling interface 507 and enters the optical measurement system 500. Similarly, the beam divergence half angle θ R represents the divergence of the first return beam 504 along the first dimension as it exits the sample and enters the optical measurement system 500. Although the first return beam 504 is shown as passing through the convergence point 510 at normal incidence, it will be appreciated that in some cases, the first return beam 504 may pass through the convergence point 510 at non-normal incidence.

[0145] When the sample is placed against the collection site 510, the first return beam 504 can be projected to emanate from the sample as a first projected return beam 506. If no scattering occurs within the sample, the first projected return beam 506 represents the path that light would travel through the sample to become part of the first return beam 504. In other words, the first projected return beam 506 represents an extension of the trajectory of the first return beam 506 as it leaves the sample. However, in practice, the actual photons collected as part of the first return beam 504 may take paths that deviate from the projected return beam 506.

[0146] The first steered beam 504 can be configured such that the first projected return beam 506 has a transition region 508 (also referred to herein as the "first transition region 508") within the target sample. The first transition region 508 represents the location where the first projected return beam 506 transitions along a first dimension from a diverging beam (as shown by the diverging portion 506a of the first projected return beam 506) to a converging beam (as shown by the converging portion 506b of the first projected return beam 506). For example, in some variations, the collection optics subassembly 524 is configured to image a region within the sample onto the first detector element 520. Thus, the first detector element 520 can be positioned at the image plane of the collection optics subassembly 524, and the transition region 508 can be positioned at the object plane of the collection optics subassembly 524. In this manner, light rays projected to originate from a common point in the transition region 508 (e.g., the first and second light rays 504a, 504b of the first return beam 504) will be directed to a common location on the first detector element 520.

[0147] The first projected return beam 506 will have a beam width W at the transition region 508. P , and the beam divergence half angle θ along the first dimension P The depth d in the target sample P It should be understood that the beam width W P and beam divergence half angle θ P and depth d P The wavelength may depend on the beam characteristics of the first return beam 504 (eg, the beam width W R , beam divergence half angle θ R and the beam direction of the first return beam 504) and certain sample properties of the target sample (e.g., refractive index). For example, a change in the refractive index at the interface between the collection site 510 and the sample can cause the light to refract as it leaves the sample and enters the sampling interface 507 to form the first return beam 504. Although the transition region 508 is Figure 5A508 is shown as being parallel to the outer surface of the sampling interface 507 , but it will be appreciated that, depending on the properties of the first return beam 504 , the transition region 508 may be tilted at a non-zero angle relative to the sampling interface 507 .

[0148] Increase the beam divergence half angle θ of the first return beam 504 R and / or beamwidth W R The etendue of the first return beam 504 (and thereby the etendue of the first projected return beam 506) can be increased, which can increase the sample volume measured by the measurement channel associated with the first detector element 520. For example, in some variations, the optical measurement system 500 is configured to collect and measure, using the collection architecture 502 and the first detector element 520, a beam divergence half-angle θ of at least 5 degrees along a first dimension as the first return beam 504 enters the collection site 510, as measured in air. R In some of these variations, when the first return beam 504 leaves the transmission site 308, the diverging return beam has a beam divergence half-angle θ of at least fifteen degrees measured in air along the first dimension. R .

[0149] Similarly, in some variations, the optical measurement system 500 is configured to collect and measure a first return beam 504 that collects a first projected return beam 506 from a target sample (such as discussed in more detail herein), wherein the first projected return beam 506 has a beam divergence half-angle θ of at least three degrees along a first dimension at a transition region 508. P , as measured in the target sample. In other words, at any given point along the transition region 508, the first return beam 504 is projected to receive projected light from that point that spans at least six degrees (e.g., ± three degrees around the central ray projected to pass through the point). In some of these variations, the beam divergence half angle θ, as measured in the target sample, is P At least ten degrees along the first dimension.

[0150] It should be understood that the first return beam 504, and thus the first projected return beam 506, may have different beam properties in other dimensions. For example, Figure 5B Shown Figure 5A For ease of illustration, the sampling interface 507 is not shown. Figure 5B , and line 540 represents the point at which the first return beam 504 enters the sampling interface. As shown, when the first return beam 504 enters the sampling interface, the beam width of the first return beam 504 is in the first dimension (e.g., Figure 5Bplane shown in the XZ plane) may be different from the first dimension in a second dimension perpendicular to the first dimension (e.g., in Figure 5B In some variations, first return beam 504 has a beamwidth in the second dimension that is at least four times greater than the beamwidth in the first dimension. In some of these variations, the beamwidth in the second dimension is at least eight times greater than the beamwidth in the first dimension.

[0151] Similarly, the beam vergence of the first return beam 504 along the first dimension (eg, the beam vergence half angle θ R ) may be different from the beam vergence along the second dimension. For example, while the first return beam 504 (and thus the first projected return beam 506) may diverge in the first dimension upon entering the sampling interface, the first return beam 504 may be collimated in the second dimension. Alternatively, the first return beam 504 may be converging in the second dimension. In other variations, the first return beam 504 may be configured to diverge in the second dimension. In these cases, the beam vergence of the first return beam 504 in the second dimension may be the same as or different from the beam vergence in the first dimension.

[0152] In some cases, the collection architecture 502 can be configured to collect multiple return beams simultaneously, with each return beam being measured by a different detector element. In this way, the optical measurement system 500 can be able to measure the optical properties of a given emission beam (e.g., Figure 3A and Figure 3B Variations of the described optical measurement system 500 utilize different portions of light emitted by the collection optics subassembly (e.g., collection optics subassembly 524) to form different measurement channels of the optical measurement system 300. In some of these variations, the same collection optics subassembly (e.g., collection optics subassembly 524) can be configured to capture multiple return beams simultaneously.

[0153] For example, Figure 5BA second detector element 530 is shown (shown in dashed lines for ease of illustration). The collection architecture 502 of the optical measurement system 500 is configured to collect the second return beam 514, which is directed to and measured by the second detector element 530 as part of a second measurement channel of the optical measurement system 500. Specifically, the collection optics subassembly 524 is configured to receive the second return beam 514 and shape it to form a second measurement beam 536. The collection optics subassembly 524 is also configured to direct the second measurement beam 536 to the second detector element 530. In other words, the second return beam 514 defines a second set of position and angle pairs at the collection site 510. Any light that enters the optical measurement system 500 through the collection site 510 at a position / angle pair associated with the second return beam 514 will be directed (e.g., via the collection optics subassembly 524 and the second measurement beam 536) to the second detector element 530 and measured by the second detector element.

[0154] The collected second return beam 514 can be similar to the first return beam 504 (e.g., it can be a diverging beam projected from the second projected beam 516, with the second projected beam having a second transition region 518 between the diverging portion 516a and the converging portion 516b of the second projected beam 516). The first transition region 508 can be positioned at a different region having the sample being measured than the second transition region 518, such that the first detector element 520 and the second detector element 530 (and thus the first and second measurement channels of the optical measurement system 500) measure light projected to originate from different regions within the sample. The collection optics subassembly 524 can also be associated with additional detector elements (e.g., a third detector element) such that the collection optics subassembly 524 collects additional return beams, each associated with a corresponding projected return beam having a transition region.

[0155] The optical measurement system can be configured such that when the collection architecture 502 is used to collect a set of return beams (e.g., first return beam 504, second return beam 514, etc.) from a target sample, the corresponding transition regions of some or all of these beams are positioned at angle-independent sample regions for their corresponding measurement channels. In other words, the first transition region 508 is positioned at an angle-independent region of the target sample for the first measurement channel defined by the first detector element 520. In this manner, the first complete return beam 504 is projected to intersect the first angle-independent region of the target sample (e.g., angle-independent with respect to the light measured by the first measurement channel). Similarly, the second transition region 518 is positioned at an angle-independent region of the target sample for the second measurement channel defined by the second detector element 530. Thus, the entire second return beam 514 is projected to intersect the second angle-independent region of the target sample (e.g., angle-independent with respect to the light measured by the second measurement channel).

[0156] In this way, the path length distribution of each measurement channel is independent of the angular range over which the measurement channel collects light. Specifically, the path length distribution of each light ray measured by the first detector element 520 (e.g., the beam divergence half angle θ across the first return beam 504) is R and the beam divergence half angle θ of the projected return beam 506 P ) will have approximately the same path length distribution for the target wavelength. Similarly, the path length distributions of the individual light rays measured by the second detector element 530 will have approximately the same path length distribution for the target wavelength. Thus, increasing these beam divergences increases the etendue of the return beams 504, 514 and, therefore, can increase the sample volume measured by these measurement channels without significantly changing the corresponding path length distributions of the light measured by these measurement channels.

[0157] For a given measurement channel, light may be projected for emission toward and / or collection from an angle-independent sample region. Figures 6A to 6B The collection of light projected to emit an angle-independent sample area is shown. Specifically, Figure 6AA partial cross-sectional view of an optical measurement system 600 for measuring a target sample 602 is shown. Specifically, the optical measurement system 600 includes a transmission architecture (schematically depicted as a block 604) and a sampling interface 607 defining a transmission site 608 and a collection site 610 as described herein. The optical measurement system 600 includes a first measurement channel, and the transmission architecture is configured to transmit an emission light beam 614 through the transmission site 608 into the target sample 602. The first measurement channel also includes a detector element (not shown) configured to receive a portion of light from the emission light beam 614 that is returned to the optical measurement system through the collection site 610.

[0158] Figure 6A A first sample region 640 is shown on the collecting side of the measurement channel independent of the first measurement channel angle. Figure 6A Two example light rays (first light ray 611a and second light ray 611b) are depicted in FIG, which represent two possible light rays that may be collected by the first measurement channel. The first light ray 611a and the second light ray 611b are both projected to pass through the first sample region 640 (e.g., via first and second projected light rays 612a, 612b, respectively, that intersect the first sample region 640). Figure 6A Also shown is a first sampling volume 616a, which represents a possible optical path of a first measurement channel that enters target sample 602 via emission light beam 614 and exits target sample 602 along the trajectory of first ray 611a (e.g., at the position and ray angle of first ray 611a). Similarly, a second sampling volume 616b represents a possible optical path of the first measurement channel that enters target sample 602 via emission light beam 614 and exits target sample 602 along the trajectory of second ray 611b (e.g., at the position and ray angle of second ray 611b).

[0159] Because the first sample area 640 is angle independent, the light collected along the trajectory of the first ray 611a will have a path length distribution that is approximately the same as the path length distribution of the light collected along the trajectory of the second ray 611b (e.g., similar to Figure 4C 430). Additional light rays projected to intersect the first sample area 640 can be collected without significantly changing the overall path length distribution of the first measurement channel. Even though light traveling along the trajectories of the first and second light rays 611a, 611b samples different sampling volumes 616a, 616b, the light will have approximately the same path length distribution, allowing the optical measurement system to increase the beam vergence of the collected return light beam for a given measurement channel while still maintaining the desired path length distribution.

[0160] In some cases, the optical measurement system can be configured to: for a given measurement channel, i) emit light projected to intersect an angle-independent sample region, and ii) collect light projected to intersect a second angle-independent sample region. Figure 6B Shown for measuring Figure 6A FIG. 6 is a partial cross-sectional view of another variation of an optical measurement system 620 for a target sample 602 . Specifically, the optical measurement system 620 includes a sampling interface 607 that defines the transmitting site 608 and the collecting site 610 .

[0161] The optical measurement system 620 can be configured to project a first emission light beam (whose boundaries are represented by first and second light rays 621a, 621b and corresponding first and second projection light rays 622a, 622b) toward a first sample region 642 that is angle-independent for the first measurement channel. Similarly, the optical measurement system 620 is configured to collect a first return light beam (whose boundaries are represented by third and fourth light rays 631a, 631b and corresponding third and fourth projection light rays 632a, 632b) for measurement by the detector elements of the first measurement channel. The first return light beam is projected to emanate from a second sample region 644 that is angle-independent for the first measurement channel. In these cases, any light measured by the first measurement channel will enter the target sample 602 along a trajectory that intersects the first angle-independent sample area 642 (e.g., along the trajectory of the first ray 621a, the second ray 621b, or another ray projected to intersect the first sample area 642) and exit the target sample 602 along a trajectory that intersects the second angle-independent sample area 644 (e.g., along the trajectory of the third ray 621a, the fourth ray 621b, or another ray projected to intersect the second sample area 644).

[0162] Regardless of the combination of incident and exit trajectories, the light measured by the first measurement channel of the optical measurement system 620 will have approximately the same path length distribution. For example, Figure 6B A first sampling volume 650a is shown, which represents a possible optical path of the first measurement channel entering the target sample 602 along the trajectory of the first ray 621a and exiting the target sample 602 along the trajectory of the third ray 631a. Similarly, a second sampling volume 650b represents a possible optical path of the first measurement channel entering the target sample 602 along the trajectory of the second ray 621b and exiting the target sample 602 along the trajectory of the fourth ray 631b. The light collected from the first sampling volume 650a and the second sampling volume 650b will have approximately the same path length distribution (e.g., similar to Figure 4C430 ). Similarly, any other combination of trajectories (e.g., entering target sample 602 along the trajectory of first ray 621 a and exiting along the trajectory of fourth ray 631 b, entering along the trajectory of second ray 621 a and exiting along the trajectory of third ray 631 a) will also have approximately the same path length distribution. In this way, the optical measurement system can increase the etendue associated with both emitting and collecting light into the sample.

[0163] Figures 7 to 9D An example of an optical measurement system configured to project light toward and / or collect light projected from an angle-independent sample area for one or more measurement channels is shown. Figure 7 A partial cross-sectional side view of an optical measurement system 700 is shown, which is configured to project light toward an angle-independent sample area for a first measurement channel. Specifically, the optical measurement system 700 includes a sampling interface 707 having a transmission site 708 and a collection site 710 (as described in more detail herein), a transmission architecture 702, and a collection architecture 704. The transmission architecture 702 is configured to generate and transmit an emission light beam 711 that exits the sampling interface 707 through the transmission site 708. Similarly, the collection architecture 704 includes a detector element 706 and is configured to collect a return light beam 712 that enters the sampling interface 707 through the collection site 710 and direct the return light beam 712 to the detector element 706.

[0164] When the transmitting architecture 702 transmits the emission beam 711 into the target sample 740 (or another measurement sample having a predetermined set of sample characteristics), at least a portion of the emission beam 711 is returned to the optical measurement system 700 as part of the return beam 712. In other words, the detector element 706 measures the portion of the emission beam 711 that is returned from the measured sample to the optical measurement system 700. In this manner, when the transmitting architecture transmits the emission beam 711, the detector element 706 forms a first measurement channel.

[0165] The transmission architecture 702 is configured such that the emission beam 711 projects the projected emission beam 714 into the sample being measured. The emission beam 711 and the projected emission beam 714 may have the same configuration as described above. Figure 3A and Figure 3B Specifically, the emission beam 711 is projected along a first dimension (e.g., along a plane using Figure 7In this manner, emission beam 711 projects a projected emission beam 714 that has a converging portion 714a along the first dimension upon exiting sampling interface 707 and transitions to a diverging portion 714b at transition region 716. In some cases, for example Figure 7 As shown in FIG, the transmission architecture 702 can be configured such that the emission beam 711 (and thus the projected emission beam 714) is angled along a first dimension toward the collection site 710. This can preferably direct light toward the collection site 710, which can increase the collection efficiency of the first measurement channel.

[0166] The optical measurement system 700 is also configured such that when the emission beam 711 is emitted into the target sample 740, the transition region 716 coincides with the angle-independent sample region for the first measurement channel. In this manner, each ray from the emission beam 711 is projected to intersect the angle-independent sample region for the first measurement channel. Consequently, the light measured by the detector element 706 when the transmitting architecture emits the emission beam 711 (i.e., the light measured by the first measurement channel) will have approximately the same path length distribution regardless of where the individual photons exit the sampling interface 707.

[0167] The return beam 712 is projected to emanate from a projected return beam 718 in a sample being measured (eg, target sample 740). Figure 7 As shown, the emission beam 711 and the return beam 712 are configured so that the projected return beam 718 intersects the diverging portion 714b of the projected emission beam 714 in a first dimension. Although individual photons may not remain within the projected optical path, configuring the emission beam 711 and the return beam 712 in this manner can facilitate the collection of light that has passed through the transition region 716 of the projected emission beam 714. Figure 7 In the illustrated variation, the collection architecture 704 is configured to collect a return beam 712 that is collimated in a first dimension upon entering the sampling interface 707, however, it should be understood that the return beam 712 may alternatively converge or diverge along the first dimension. It should also be understood that the optical measurement system 700 may include any components that may be required to generate the transmitted beam 711 and collect the return beam 712, such as those described herein. For example, the transmission architecture 702 may be collimated in a first dimension upon entering the sampling interface 707. Figure 7 7. Shown therein is a beam generator 720 configured to generate an output beam 722 and a transmit optics subassembly 724 including one or more lens elements configured to generate a transmit beam 711 from the output beam 722.

[0168] Figure 8A partial cross-sectional side view of an optical measurement system 800 is shown that is configured to collect light projected to be emitted from an angle-independent sample area for a first measurement channel. Specifically, the optical measurement system 800 includes a sampling interface 807 having a transmission site 808 and a collection site 810 (as described in more detail herein), a transmission architecture 802, and a collection architecture 804. The transmission architecture 802 is configured to generate and transmit an emission light beam 811 that exits the sampling interface 807 through the transmission site 808. Similarly, the collection architecture 804 includes a detector element 806 and is configured to collect a return light beam 812 that enters the sampling interface 807 through the collection site 810 and direct the return light beam 812 to the detector element 806.

[0169] When the transmitting architecture 802 transmits the emission beam 811 into the target sample 840 (or another measurement sample having a predetermined set of sample characteristics), at least a portion of the emission beam 811 is returned to the optical measurement system 800 as part of the return beam 812. In other words, the detector element 806 measures the portion of the emission beam 811 that is returned from the measured sample to the optical measurement system 800. In this manner, when the transmitting architecture transmits the emission beam 811, the detector element 806 forms a first measurement channel of the optical measurement system 800.

[0170] The return beam 812 is projected to emit from the measured sample (eg, target sample 840) a projected return beam 818. The return beam 812 and the projected return beam 818 may have the same configuration as described above. Figure 5A and Figure 5B Specifically, the return beam 812 is directed along a first dimension (e.g., along a plane using a laser beam) upon entering the sampling interface 807. Figure 8 In this manner, the emission beam 812 is projected to emanate from a projected return beam 818 that has a diverging portion 818a along the first dimension upon entering the sampling interface 807 and transitions from a converging portion 818b at a transition region 816. In some cases, such as Figure 8 As shown, the collection architecture 804 can be configured such that the return beam 812 (and thus the projected return beam 818) is angled in a first dimension away from the transmission site 808. This can facilitate collection of light from the direction of the transmission site 808, which can increase the collection efficiency of the first measurement channel.

[0171] The optical measurement system 800 is also configured such that when the emission beam 811 is emitted into the target sample 840, the transition region 816 coincides with the angularly independent sample region for the first measurement channel. In this manner, each ray of light collected as part of the return beam 812 is projected to emanate from the angularly independent sample region for the first measurement channel. Consequently, the light measured by the detector element 806 when the transmitting architecture emits the emission beam 811 (i.e., the light measured by the first measurement channel) will have approximately the same path length distribution regardless of where the individual photons enter the sampling interface 807 as part of the return beam 812.

[0172] The transmitting architecture 802 is configured to generate the transmit beam 811 so that the projected transmit beam 814 intersects the converging portion 818b of the projected return beam 818. Although individual photons may not remain within the projected optical path, configuring the transmit beam 811 and the return beam 812 in this manner can facilitate the collection of light that has passed through the transition region 816 of the projected return beam 818. Figure 8 In the illustrated variation, the transmit architecture 802 is configured to transmit a transmit beam 811 that is collimated in a first dimension. However, it should be understood that the transmit beam 812 may optionally be convergent or divergent along the first dimension.

[0173] It should also be understood that the optical measurement system 800 may include any components that may be required to generate the transmitted light beam 811 and collect the returned light beam 812, such as those described herein. Figure 8 is shown with a beam generator 820 configured to generate a transmit beam 811. The collection architecture 804 is Figure 8 806 is shown having a collection optics subassembly 824 comprising one or more lens elements and configured to receive and shape the return beam 812 to form a measurement beam 826 that is incident on the detector element 806.

[0174] Figure 9A900 is a partial cross-sectional side view of an optical measurement system configured to i) project light toward a first angularly independent sample region of a first measurement channel and ii) collect light projected to emit from a second angularly independent sample region of the first measurement channel. Specifically, the optical measurement system 900 includes a sampling interface 907 (as described in more detail herein) having a transmission site 908 and a collection site 910, a transmission architecture 902, and a collection architecture 904. The transmission architecture 902 is configured to generate and transmit an emission light beam 911 that exits the sampling interface 907 through the transmission site 908. Similarly, the collection architecture 904 includes a detector element 906 and is configured to collect a return light beam 912 that enters the sampling interface 907 through the collection site 910 and direct the return light beam 912 to the detector element 906.

[0175] When the transmitting architecture 902 transmits the emission beam 911 into the target sample 940 (or another measurement sample having a predetermined set of sample characteristics), at least a portion of the emission beam 911 is returned to the optical measurement system 900 as part of the return beam 912. In other words, the detector element 906 measures the portion of the emission beam 911 that is returned from the measured sample to the optical measurement system 900. In this manner, when the transmitting architecture 902 transmits the emission beam 911, the detector element 906 forms a first measurement channel.

[0176] The transmission architecture 902 is configured such that the emission beam 911 projects the projected emission beam 914 into the sample being measured. The emission beam 911 and the projected emission beam 914 may have the same configuration as described above. Figure 3A and Figure 3B Specifically, the emission beam 911 is projected along a first dimension (e.g., along a plane using Figure 9A In this manner, emission beam 911 projects a projected emission beam 914 that has a converging portion 914a along a first dimension upon exiting sampling interface 907 and transitions to a diverging portion 914b at a first transition region 916a. In some cases, for example Figure 9A As shown in , the transmission architecture 902 can be configured such that the emission beam 911 (and thus the projected emission beam 914) is angled along a first dimension toward the collection site 910. This can preferably direct the light toward the collection site 910, which can increase the collection efficiency of the first measurement channel.

[0177] The optical measurement system 900 is also configured such that when the emission beam 911 is emitted into the target sample 940, the first transition region 916a coincides with the first angle-independent sample region for the first measurement channel. In this manner, each ray from the emission beam 911 is projected to intersect the angle-independent sample region for the first measurement channel. Consequently, the light measured by the detector element 906 when the transmitting architecture emits the emission beam 911 (i.e., the light measured by the first measurement channel) will have approximately the same path length distribution regardless of where the individual photons exit the sampling interface 907.

[0178] Similarly, the return beam 912 is projected to emanate from the projected return beam 918 in the sample being measured (eg, target sample 940). The return beam 912 and the projected return beam 918 may have the same configuration as described above with respect to FIG. Figure 5A and Figure 5B Specifically, the return beam 912 is directed along a first dimension (e.g., along a direction) upon entering the sampling interface 907. Figure 9A In this manner, the return beam 912 is projected to emanate from a projected return beam 918 having a diverging portion 918a along the first dimension upon entering the sampling interface 907 and transitioning from a converging portion 918b at a second transition region 916b. In some cases, such as Figure 9A As shown, the collection architecture 904 can be configured such that the return beam 912 (and thus the projected return beam 918) is angled in a first dimension away from the transmission site 908. This can facilitate the collection of light from the direction of the transmission site 908, which can further increase the collection efficiency of the first measurement channel.

[0179] The optical measurement system 900 is also configured such that when the emission beam 911 is emitted into the target sample 940, the second transition region 916b coincides with the second angularly independent sample region for the first measurement channel. In this manner, each ray of light collected as part of the return beam 912 is projected to emanate from the angularly independent sample region for the first measurement channel. Consequently, the light measured by the detector element 906 when the transmitting architecture emits the emission beam 911 (i.e., the light measured by the first measurement channel) will have approximately the same path length distribution regardless of where the individual photons enter the sampling interface 907 as part of the return beam 912.

[0180] The transmit architecture 902 and the collection architecture 904 can be configured such that a diverging portion 914b of the projected emission beam 914 intersects a converging portion 914c of the projected return beam 918. This can help facilitate the collection of light within the target sample 940 that has passed through both the first transition region 916a and the second transition region 916b. To generate the emission beam 911, the transmit architecture 902 can include a beam generator 920 and a transmit optics subassembly 924 including one or more lens elements, which can be configured in any suitable manner, such as described herein. The beam generator 920 is configured to generate an output beam 922 that diverges in at least one dimension (e.g., at least a first dimension) and is received and shaped by the transmit optics subassembly 924 to form the emission beam 911. Similarly, the collection architecture 904 can include a collection optics subassembly 926 including one or more lens elements. Collection optics subassembly 926 may be configured in any suitable manner, such as described herein, and is configured to receive return beam 912 and shape it to form a first measurement beam 928 that is incident on detector element 906 .

[0181] Although Figure 9A The optical measurement system 900 shown in FIG. 9 is depicted as including a single detector element 906 , but in other variations, the optical measurement systems described herein may include multiple detector elements that simultaneously form multiple measurement channels. Figure 9B FIG. 9 is a partial cross-sectional side view of a device incorporating an optical measurement system 930 as described herein. The optical measurement system 930 is similar to Figure 9A The optical measurement system 900 is configured to: i) project light toward a sample region that is angularly independent for a first plurality of measurement channels, and ii) collect light projected to emit from a plurality of sample regions, each of the plurality of sample regions being angularly independent for a different corresponding measurement channel.

[0182] Specifically, the optical measurement system 930 includes a sampling interface 907 having a transmission site 908 and a collection site 910 (as described in more detail herein), a transmission architecture 932, and a collection architecture 934. The transmission architecture 932 is configured to generate and transmit an emission light beam 941 that exits the sampling interface 907 through the transmission site 908. Similarly, the collection architecture 934 includes a plurality of detector elements 936a-936c and is configured to collect a plurality of return light beams 942a-942c that enter the sampling interface 907 through the collection site 910 and direct the return light beams 942a-942c to the detector elements 936a-936c. For example, the plurality of detector elements 936a-936c are arranged at Figure 9B 936a, a second detector element 936b, and a third detector element 936c.

[0183] The collection architecture 934 is configured to collect a first return beam 942a directed to and measured by a first detector element 936a, a second return beam 942b directed to and measured by a second detector element 936b, and a third return beam 942c directed to and measured by a third detector element 936c. Each of the plurality of return beams 942a-942c defines a different set of position and angle pairs at the collection site 910, such that light entering the sampling interface 907 at a given position / angle pair (e.g., at a particular angle of incidence for a particular position) will be routed to a given detector element among the plurality of detector elements 936a-936c. It will be appreciated that the different return beams may overlap at the collection site 910. For example, for light entering the sampling interface at a particular position at the collection site 910 where the first and second return beams 942a, 942b overlap, photons entering that position at a first angle of incidence may be routed to the first detector element 936a, and photons entering that position at a different, second angle of incidence may be routed to the second detector element 936b. It should be understood that the plurality of detector elements 936a-936c alternatively includes two or four or more detector elements, as desired.

[0184] When the transmit architecture 932 transmits the emission beam 941 into a target sample or another measurement sample having a predetermined set of sample characteristics (not shown), at least a portion of the emission beam 941 is returned to the optical measurement system 930 as part of each of the plurality of return beams 942a-942c. In other words, each of the plurality of detector elements 936a-936c measures a different corresponding portion of the emission beam 941 returned from the sample being measured to the optical measurement system 930. In this manner, when the transmit architecture 932 transmits the emission beam 941, each of the plurality of detector elements 936a-936c forms a different measurement channel (e.g., the first detector element 936a forms a first measurement channel, the second detector element 936b forms a second measurement channel, and the third detector element 936c forms a third measurement channel).

[0185] The transmission structure 932 is configured so that the emission beam 941 projects the projected emission beam 944 into the sample being measured. The emission beam 941 and the projected emission beam 944 may have the same configuration as described above. Figure 3A and Figure 3B Specifically, the emission beam 941 is projected along a first dimension (e.g., along a plane using Figure 9BIn this manner, emission beam 941 projects a projected emission beam 944 that has a converging portion along the first dimension upon exiting sampling interface 907 and transitions to a diverging portion at emission transition region 946 (at Figure 9B Only the convergent part is depicted). In some cases, e.g. Figure 9B As shown in , the transmission architecture 932 can be configured such that the emission beam 941 (and thus the projected emission beam 944) is angled along a first dimension toward the collection site 910. This can preferably direct light toward the collection site 910, which can increase the collection efficiency of the first measurement channel.

[0186] The optical measurement system 930 is also configured such that when the emission beam 941 is emitted into a target sample (not shown) as described herein, the emission transition region 946 coincides with a first sample region that is angularly independent for at least one of the plurality of measurement channels. In some cases, the sample region is angularly independent for each of the plurality of measurement channels. Specifically, the emission transition region 946 coincides with a first sample region that is angularly independent for each of the first, second, and third measurement channels. In this manner, the light measured by each of the plurality of detector elements 936a-936c when the transmitting architecture emits the emission beam 941 will have approximately the same path length distribution, regardless of where the individual photons exit the sampling interface 907. However, it should be understood that the path length distribution of the light measured by the first detector element 936a may still differ (e.g., have a different shape and / or median path length) from the path length distribution of the light measured by the second detector element 936b and / or the third detector element 936c.

[0187] In other cases, the emission transition region 916 may coincide with the first sample region that is not angle-independent for each measurement channel. For example, the first sample region may be angle-independent for the second measurement channel (e.g., light measured by the second detector element 936b), but may not be angle-independent for the first and third measurement channels (e.g., light measured by the first and third detector elements 936a, 936c, respectively). In these cases, it may be desirable to lose some path length control in exchange for increasing the collection efficiency of these angle-dependent measurement channels. This angular dependence may be taken into account when determining sample properties (e.g., information from the angle-dependent measurement channels may be given less weight than the angle-independent measurement channels).

[0188] A plurality of return beams 942a-942c are projected to be emitted from a plurality of projected return beams 948a-948c in the sample being measured, such that each return beam is projected to be emitted from a corresponding projected return beam. Specifically, a first return beam 942a is projected to be emitted from a first projected return beam 948a, a second return beam 942b is projected to be emitted from a second projected return beam 948b, and a third return beam 942c is projected to be emitted from a third projected return beam 948c. Each of the return beams 942a-942c and its corresponding projected return beam may have a configuration as described above with respect to Figure 5A and Figure 5B Any characteristics described for the return beam 504 and the projected return beam 506.

[0189] exist Figure 9B In the illustrated variation, each of the return beams 942a-942c travels along a common first dimension (e.g., along Figure 9B In this manner, each of the plurality of return beams 942a-942c is projected to emanate from a projected return beam having a diverging portion along a first dimension upon entering the sampling interface 907 and transitioning from a converging portion at a corresponding collection transition region (at Figure 9B Only the diverging portions of the projected return beams 948a-948c are shown. Thus, the plurality of return beams 942a-942c are associated with a plurality of collection transition regions 947a-947c (e.g., a first projected return beam 948a has a first collection transition region 947a, a second projected return beam 948b has a second collection transition region 947b, and a third projected return beam 948c has a third collection transition region 947c).

[0190] Optical measurement system 930 is also configured such that when emission beam 941 is emitted into a target sample, multiple collection transition regions 947a-947c coincide with multiple sample regions that are angularly independent for each of the multiple measurement channels. Specifically, first collection transition region 947a coincides with a second sample region that is angularly independent of the first measurement channel (e.g., light measured by first detector element 936a), second collection transition region 947b coincides with a third sample region that is angularly independent of the second measurement channel (e.g., light measured by second detector element 936b), and third collection transition region 947c coincides with a fourth sample region that is angularly independent of the third measurement channel (e.g., light measured by third detector element 936c). In this manner, each ray of light collected as part of the return beam for a given measurement channel is projected to emanate from a sample region that is angularly independent for that measurement channel. Consequently, each of the multiple detector elements 936a-936c can increase the amount of light it collects while maintaining path length control as discussed herein.

[0191] Although Figure 9B 948a-948c. Although not shown in FIG. 949, it should be understood that the transmit architecture 932 and the collection architecture 934 can be configured so that the diverging portion of the projected emission beam 914 intersects the converging portion of each of the projected return beams 948a-948c. For each measurement channel, this can help facilitate the collection of light that has passed through the emission transition region 936 and the corresponding one of the collection transition regions 947a-947c within the measurement sample.

[0192] exist Figure 9B In the illustrated variation, the collection architecture 934 includes a collection optics subassembly 956. The collection optics subassembly 956 includes one or more lens elements and is configured to receive the plurality of return beams 942a-942c and shape them to form a plurality of measurement beams 958a-958c that are incident on the plurality of detector elements 936a-936c. Specifically, the collection optics subassembly 956 shapes the first return beam 942a into a first measurement beam 958a that is measured by the first detector element 936a, shapes the second return beam 942b into a second measurement beam 958b that is measured by the second detector element 936b, and shapes the third return beam 942c into a third measurement beam 958c that is measured by the third detector element 936c.

[0193] The collection optics subassembly 956 may be configured in any suitable manner to define the return beams 942a-942c and to route each of these return beams 942a-942c to a corresponding detector element in the plurality of detector elements 936a-936c. Figure 9BIn the variation shown, the collection optics subassembly 956 includes an imaging lens 953 and a relay lens 955 separated by an aperture 957. In some variations, the imaging lens 953 and the relay lens 955 are each configured as a cylindrical lens, which can allow the profile of the return beams 942a-942c to extend in a second dimension perpendicular to the first dimension. Figure 9B Examples of collection optics subassemblies used in conjunction with the optical measurement system 930 are described herein with respect to Figures 14A to 17B Describe in more detail.

[0194] To generate the transmit beam 941, the transmit architecture 932 may include a beam generator 950 and a lens element 952 including one or more lens elements (in the Figure 9B 954 ), the one or more lens elements of which may be configured in any suitable manner such as described herein. The beam generator 950 is configured to generate an output beam 952 that diverges in at least one dimension (e.g., at least a first dimension) and is received and shaped by the transmit optics subassembly 954 to form an emission beam 941. In an example, the one or more lenses of the transmit optics subassembly may be formed as part of one or more common substrates along with the one or more lenses of the collection optics subassembly 956. For example, in Figure 9B In the illustrated variation, the lens of the transmit optics subassembly 954 and the imaging lens 953 of the collection optics subassembly 956 are formed as part of a common substrate 959. For example, a first portion of the substrate 959 may be etched to define the lens of the transmit optics subassembly 954, and a second portion of the substrate 959 may be etched to define the imaging lens 953. Forming the imaging lens 953 and the lens of the transmit optics subassembly 954 from different portions of the common substrate 959 may allow for precise relative positioning of these lenses within the optical measurement system 930.

[0195] The optical measurement system 930 is configured such that light returning from the emission beam 941 is collected by a single collection site 910, but in other variations, the optical measurement system as described herein may be configured to use multiple collection sites to measure light returning from a single emission beam. For example, Figure 9C and Figure 9D A partial cross-sectional side view and a perspective view are shown, respectively, of another variation of an optical measurement system 960. The optical measurement system 960 is similar to Figure 9BOptical measurement system 930 is similar to optical measurement system 960, except that optical measurement system 960 is configured to project an emission light beam and collect different portions of the returned light using multiple collection sites. Each collection site can be associated with a different set of measurement channels. In some variations, optical measurement system 960 can be configured to project light toward a sample region that is angularly independent for i) one or more measurement channels associated with a first collection site and ii) one or more measurement channels associated with a second collection site. Additionally or alternatively, optical measurement system 960 is configured to collect light projected from multiple sample regions, each sample region being angularly independent for a different corresponding measurement channel.

[0196] Specifically, the optical measurement system 960 includes a transmitting architecture 962, a collecting architecture 964, and a sampling interface 907 having a transmitting site 908, a first collecting site 910a, and a second collecting site 910b, as described in more detail herein. Figure 9C and Figure 9D In the illustrated variation, the transmission site 908 is positioned between the first collection site 910a and the second collection site 910b. The transmission architecture 962 is configured to generate and transmit an emission light beam 971 that exits the sampling interface 907 through the transmission site 908. Similarly, the collection architecture 964 includes a first set of detector elements 966a-966c associated with the first collection site 910a and a second set of detector elements 966d-966f associated with the second collection site 910b. The collection architecture 964 is configured to collect a first set of return light beams 972a-972c that enter the sampling interface through the first collection site 910a and is configured to route these return light beams 972a-972c to the first plurality of detector elements 966a-966c. Similarly, the collection architecture 964 is configured to collect a second set of return light beams 972d-972f that enter the sampling interface 907 through the second collection site 910b and to direct these return light beams 972d-972f to a second set of detector elements 966d-966f.

[0197] The first set of detector elements 966a-966c is Figure 9C and Figure 9D 966f. In the embodiment shown, the first group of detector elements 966a-966c may have a different number of detector elements than the second group of detector elements 966d-966f. In the embodiment shown, the first group of detector elements 966a-966c may have a different number of detector elements than the second group of detector elements 966d-966f. In the embodiment shown, the first group of detector elements 966a-966c may have a different number of detector elements than the second group of detector elements 966d-966f. In the embodiment shown, the first group of detector elements 966a-966c may have a different number of detector elements than the second group of detector elements 966d-966f. Figure 9C and Figure 9DIn the example shown in , a first group of detector elements 966a-966c includes a first plurality of detector elements (e.g., a first detector element 966a, a second detector element 966b, and a third detector element 966c, which may be arranged such that the second detector element 966b is positioned between the first detector element 966a and the third detector element 966c along a first dimension). A second group of detector elements 966d-966f includes a second plurality of detector elements (e.g., a fourth detector element 966d, a fifth detector element 966e, and a sixth detector element 966f, which may be arranged such that the fifth detector element 966e is positioned between the fourth and sixth detector elements 966d, 966f along the first dimension).

[0198] In these cases, the collection architecture is configured to collect a first plurality of return beams 972a-972c (e.g., first return beam 972a, second return beam 972b, and third return beam 972c) through a first collection site 910a. Each of the first plurality of return beams 972a-972c defines a different set of position and angle pairs on the first collection site 910a, such that light entering the sampling interface 907 at a given position / angle pair (e.g., at a specific angle of incidence for a specific position) will be routed to a given detector element in the first plurality of detector elements 966a-966b, as described in more detail herein. Similarly, the collection architecture is configured to collect a second plurality of return beams 972d-972f (e.g., fourth return beam 972d, fifth return beam 972e, and sixth return beam 972f) through a second collection site 910b. Each of the second plurality of return beams 972d-972f defines a different set of position and angle pairs on the second collection site 910b, such that light entering the sampling interface 907 at a given position / angle pair on the second collection site 910b (e.g., at a particular angle of incidence at a particular position) will be routed to a given detector element in the second plurality of detector elements 966d-966f. In general, light collected by the first return beam 972a is measured by the first detector element 966a, light collected by the second return beam 972b is measured by the second detector element 966b, and so on.

[0199] When the transmitting architecture 962 transmits the emission beam 971 into a target sample or another sample being measured having a predetermined set of sample characteristics (not shown), a first portion of the emission beam 941 will be returned to the optical measurement system 960 via the first collection site 910a as part of a first group of return beams 972a-972c. A second portion of the emission beam 941 will simultaneously be returned to the optical measurement system 960 via the second collection site 910b as part of a second group of return beams 972d-972f. In other words, each of the first and second groups of detector elements 976a-976c, 976d-976f measures a different corresponding portion of the emission beam 971 returned from the sample being measured to the optical measurement system 960. In this manner, when the transmitting architecture 962 transmits the emission beam 971, each of the first and second groups of detector elements 976a-976c, 976d-976f forms a different measurement channel. For example, when the transmitting architecture 962 transmits the emission beam 971, Figure 9C and Figure 9D The optical measurement system 970 shown in FIG. 1 includes a plurality of measurement channels (e.g., six measurement channels), wherein three measurement channels simultaneously measure light received through a first collection site 910 a, and three measurement channels simultaneously measure light received through a second collection site 910 b. Specifically, a first detector element 966 a forms a first measurement channel, a second detector element 966 b forms a second measurement channel, and so on.

[0200] The transmission structure 962 is configured so that the emission beam 971 projects the projected emission beam 974 into the sample being measured. The emission beam 971 and the projected emission beam 974 may have the same configuration as described above. Figure 3A and Figure 3B Specifically, the emission beam 971 is projected along a first dimension (e.g., along a plane using a laser beam) as it leaves the sampling interface 907. Figure 9C and Figure 9D In this manner, emission beam 971 projects a projected emission beam 974 that has a converging portion along the first dimension upon exiting sampling interface 907 and transitions to a diverging portion at emission transition region 976 (at Figure 9C and Figure 9D Only the convergent part is depicted in ). Figure 9C and Figure 9DIn the illustrated variation, the projected emission beam 974 exits the sampling interface 907 at normal incidence, which can result in the same amount of light being directed toward each of the first and second collection sites 910a, 910b. In other cases, the transmission architecture 962 can be configured such that the emission beam 971 (and thus the projected emission beam 974) is angled along a first dimension toward one of the collection sites. For example, if the emission beam 971 is angled toward the first collection site 910a, light can be preferentially directed toward the first collection site 910a, which can prioritize light collection at the first collection site 910a over light collection at the second collection site 910b.

[0201] The optical measurement system 960 is also configured such that when the emission beam 971 is emitted into a target sample (not shown) as described herein, the emission transition region 976 coincides with a first sample region that is angle-independent for at least one of the plurality of measurement channels. In some cases, the sample region is angle-independent for at least one measurement channel associated with the first collection site 910a and also angle-independent for at least one measurement channel associated with the second collection site 910b. In some instances of these cases, the sample region is angle-independent for each of the plurality of measurement channels (e.g., six measurement channels associated with the first and second pluralities of detector elements 966a-966c, 966d-966f). In this manner, the light measured by each of the first and second pluralities of detector elements 966a-966c, 966d-966f when the transmitting architecture is emitting the emission beam 941 will have approximately the same path length distribution, regardless of where the individual photons exit the sampling interface 907.

[0202] In other cases, the emission transition region 976 may coincide with a first sample region that is not angularly independent for each measurement channel associated with the first and second sets of detector elements 966a-966c, 966d-966f. For example, the first sample region may be angularly independent for the second measurement channel (e.g., light measured by the second detector element 966b), but may not be angularly independent for the first and third measurement channels (e.g., light measured by the first and third detector elements 966a, 966c, respectively). Similarly, the first sample region may be angularly independent for the fifth measurement channel (e.g., light measured by the fifth detector element 966c), but may not be angularly independent for the fourth and sixth measurement channels (e.g., light measured by the fourth and sixth detector elements 966d, 966f, respectively). As described herein, such angular dependence may be taken into account when determining sample properties.

[0203] In some cases, the optical measurement system 960 is configured such that some or all of the first set of detector elements 966a-966c are configured to measure a path length distribution of light that is approximately the same as the path length distribution of light measured by corresponding detector elements in the second set of detector elements 966d-966f. For example, in one example, the first detector element 966a and the fourth detector element 966d (and thus the first and fourth measurement channels) are configured to measure light having approximately the same path length distribution (e.g., a first path length distribution). Additionally or alternatively, the second detector element 966b and the fifth detector element 966e (and thus the second and fifth measurement channels) can be configured to measure light having approximately the same path length distribution (e.g., a second path length distribution, which may be different from the first path length distribution). Similarly, the third detector element 966c and the sixth detector element 966f (and thus the third and sixth measurement channels) can be configured to measure light having approximately the same path length distribution (e.g., a third path length distribution, which may be different from the first and second path length distributions).

[0204] In these cases, measurement channels configured to measure light of substantially the same path length distribution can be combined, which can allow the outputs of multiple detector elements to be treated as a single signal for the purpose of determining one or more sample properties as described herein. For example, the output signals of the first and fourth measurement channels can be combined to form a first combined output signal, the output signals of the second and fifth measurement channels can be combined to form a second combined output signal, and the output signals of the third and sixth measurement channels can be combined to form a third combined output signal. Overall, this can increase the amount of light collected for a given path length distribution (or set of path length distributions) (and across a larger sampling volume), which can improve the accuracy of spectral measurements performed by optical measurement system 970.

[0205] With respect to the collection architecture 964, a first set of return beams 972a-972c are projected to emanate from the first set of projected return beams 978a-978c, and a second set of return beams 972d-972f are projected to emanate from the second set of projected return beams 978d-978f. Specifically, the first return beam 972a is projected to emanate from the first projected return beam 978a, the second return beam 972b is projected to emanate from the second projected return beam 978b, the third return beam 972c is projected to emanate from the third projected return beam 978c, the fourth return beam 972d is projected to emanate from the fourth projected return beam 978d, the fifth return beam 972e is projected to emanate from the fifth projected return beam 978e, and the sixth return beam 972f is projected to emanate from the sixth projected return beam 978f. Each of the return beams 972a-972c and its corresponding projected return beam may have a configuration as described above with respect to Figure 5A and Figure 5B Any characteristics described for the return beam 504 and the projected return beam 506.

[0206] exist Figure 9C and Figure 9D In the illustrated variation, each of the first and second sets of return beams 972a-972c, 972d-972f travels along a common first dimension (e.g., along Figure 9C In this manner, each of the first set of return beams 972a-972c and the second set of return beams 972d-972f is emitted by projecting a projected return beam that has a diverging portion along the first dimension upon entering the sampling interface 907 and transitions from a converging portion at a corresponding collection transition region (at Figure 9C and Figure 9D Only the diverging portions of the return beams 942a-942c are shown. Thus, first and second sets of return beams 972a-972c, 972d-972f are associated with corresponding first and second sets of collection transition regions 977a-997c, 997d-977f.

[0207] exist Figure 9C and Figure 9DIn the example shown, where the first group of return beams 972a-972c includes a first plurality of return beams 972a-972c, the first plurality of return beams 972a-972c are associated with a first plurality of collection transition regions 977a-977c (e.g., first projected return beam 978a has a first collection transition region 977a, second projected return beam 978b has a second collection transition region 977b, and third projected return beam 978c has a third collection transition region 977c). Similarly, when the second group of return beams 972d-972f includes a second group of return beams 972d-972f, the second group of return beams 972d-972f are associated with a second group of plurality of collection transition regions 977d-977f (e.g., fourth projected return beam 978d has a fourth collection transition region 977d, fifth projected return beam 978e has a fifth collection transition region 977e, and sixth projected return beam 978f has a sixth collection transition region 977f).

[0208] The optical measurement system 930 can also be configured such that when the emission beam 971 is emitted into the target sample, the first and second sets of collection transition regions 977a-977c, 977d-977f coincide with a plurality of sample regions that are angularly independent for each of the plurality of measurement channels. In an example where the optical measurement system 970 includes six concurrent measurement channels, the six collection transition regions 977a-977f can coincide with the six angularly independent sample regions. Specifically, the first collection transition region 977a coincides with a second sample region that is angularly independent of the first measurement channel (e.g., light measured by the first detector element 967a), the second collection transition region 977b coincides with a third sample region that is angularly independent of the second measurement channel (e.g., light measured by the second detector element 966b), the third collection transition region 977c coincides with a fourth sample region that is angularly independent of the third measurement channel (e.g., light measured by the third detector element 966c), and so on. In this manner, each ray of light collected as part of the return beam for a given measurement channel is projected to emanate from an angularly independent sample region for that measurement channel. Thus, each detector element in the first and second groups of detector elements 976a-976c, 976d-976f can increase the amount of light it collects while maintaining path length control as discussed herein.

[0209] Although Figure 9C and Figure 9D978a-978c, 978d-978f. For each measurement channel, this can help facilitate the collection of light within the measurement sample that has passed through a corresponding one of the emission transition region 976 and the collection transition region 977a-977f.

[0210] To collect light from the first and second collection sites 910a, 910b, the collection architecture 964 includes a first collection optical subassembly 986a and a second collection optical subassembly 986b, each of which includes one or more lens elements. The first collection optical subassembly 986a is configured to receive the first set of return beams 972a-972c and shape them to form a first set of measurement beams 988a-988c incident on the first set of detector elements 966a-966c. Similarly, the second collection optical subassembly 986b is configured to receive the second set of return beams 972d-972f and shape them to form a second set of measurement beams 988d-988f incident on the first set of detector elements 966d-966f.

[0211] The first and second collection optics subassemblies 986a, 986b may be configured in any suitable manner, such as described herein. Figure 9C and Figure 9D As shown, the first collection optical assembly 986a may include a first imaging lens 983a and a first relay lens 985a separated by a first aperture 957a, and the second collection optical assembly 986b may include a second imaging lens 983b and a second relay lens 985b separated by a second aperture 957b. In some variations, the first imaging lens 953a and the second imaging lens 953b and the first relay lens 955a and the second relay lens 955b are each configured as a cylindrical lens, which may allow the profile of the first group of return beams 972a-972c and the second group of return beams 972d-972f to extend in a second dimension perpendicular to the first dimension (e.g., along Figure 9D The Y axis in the Cartesian coordinate system shown in ). Suitable for Figure 9C and Figure 9D Examples of collection optics subassemblies used in conjunction with the optical measurement system 970 are described herein with respect to Figures 14A to 17B Describe in more detail.

[0212] To generate the transmit beam 971, the transmit architecture 962 may include a beam generator 980 and a lens element 982 including one or more lens elements (in the Figure 9C and Figure 9DThe beam generator 980 is configured to generate an output beam 982 that diverges in at least one dimension (e.g., at least a first dimension) and is received and shaped by the transmit optics subassembly 984 to form an emission beam 971. In an example, the one or more lenses of the transmit optics subassembly may be formed as part of one or more common substrates along with the one or more lenses of the first and / or second collection optics subassemblies 986a, 986b. For example, in Figure 9C In the variation shown, the lenses of the transmitting optical subassembly 984, the first imaging lens 983a of the first collecting optical subassembly 986a, and the second imaging lens 983b of the second collecting optical subassembly 986b are formed as part of a common substrate 989 (for ease of illustration, the portion of the substrate 989 connecting these lenses is not shown). Figure 9D ). For example, a first portion of substrate 989 can be etched to define the lenses of transmit optics subassembly 984, a second portion of substrate 989 can be etched to define first imaging lens 983a, and a third portion of substrate 989 can be etched to define second imaging lens 983b. Forming these lenses from different portions of a common substrate 989 can allow for precise relative positioning between these lenses within optical measurement system 970.

[0213] Transmitter architecture for use in optical measurement systems

[0214] The optical measurement system described herein can use a range of possible transmission architectures to generate the transmitted beam. Typically, such as with respect to Figure 3A 、 Figure 3B and Figures 7 to 9D As described, the transmit architecture may include a beam generator configured to generate an output beam, and a transmit optical subassembly configured to receive the output beam and shape the output beam to form a transmit beam. 10A to 13F Examples of send architectures are described. It should be understood that these send architectures can be used as Figures 1A to 9D Part of the optical measurement system described (e.g., can be used to generate any of the output beams and emission beams described with respect to these figures), or can be used as part of any other optical measurement system as described herein where emission beams are desired.

[0215] Figure 10A and Figure 10B Shown are side views of two variations of transmit architectures configured to generate a transmit beam that is converging in at least one dimension. Figure 10AA first variation of a transmit architecture 1000 is shown having a beamformer 1002 and an imaging transmit optical subassembly 1004. The imaging transmit optical subassembly 1004 is Figure 10A 1004, but it should be understood that other variations of the imaging transmit optics subassembly 1004 may include multiple lens elements. Lens 1006 and any additional lenses of the imaging transmit optics subassembly 1004 may be configured as a one-dimensional lens (such as a cylindrical lens).

[0216] The beam generator 1002 is configured to generate beams in a first dimension (e.g., using Figure 10A The imaging transmit optical subassembly 1004 is configured to receive the output beam 1010 and shape the output beam 1010 to generate a transmit beam 1012 that converges in a first dimension. When the transmit architecture 1000 is incorporated into a system having a sampling interface (e.g., in Figure 10A , when in an optical measurement system having a transmit site 1008 shown in FIG, 1008, the emission light beam 1012 can project a projected emission light beam 1014 into a transition region 1016 in a sample being measured that is positioned in contact with the transmit site 1008. As discussed in more detail herein, the transition region 1016 represents a point where a converging portion 1014a of the projected emission light beam 1014 leaving the transmit site 1008 changes (e.g., converging in a first dimension) to a diverging portion 1014b of the projected emission light beam 1014 (e.g., diverging in the first dimension).

[0217] To project the projected emission light beam 1014 to the transition region 1016, the imaging transmit optics subassembly 1004 is configured to image the emission surface 1040 of the beamformer 1002 to the transition region 1016 in a first dimension. Specifically, if the emission surface 1040 of the beamformer (e.g., the surface of a diffuser that forms the output light beam 1010, the surface of a photonic integrated circuit that forms the output light beam 1010, etc.) is positioned at the focal plane 1018 of the transmit optics subassembly 1004, then light emitted by the emission surface will be focused at the image plane 1020 that defines the transition region 1016. For example, a ray of the output light beam 1010 emanating from a first point 1022 on the beamformer 1002 along the first dimension (e.g., for illustration, at Figure 10A 1024a - 1024c ) will be projected to a corresponding second point 1026 in the image plane 1020 (and thereby will be projected to the same second point 1026 in the transition region 1016 ).

[0218] In these cases, the beamwidth of the emission beam 1012 in the first dimension, and thus the corresponding beamwidth of the projected emission beam 1014 in the first dimension (e.g., at the transition region 1016), will depend on the beamwidth of the output beam 1010 in the first dimension. In other words, increasing the beamwidth of the output beam 1010 in the first dimension will increase the corresponding beamwidths of the first emission beam 1012 and the projected emission beam 1014. The beam vergence of the emission beam 1012 in the first dimension, and thus the corresponding beam vergence of the projected emission beam 1014 (e.g., at the transition region 1016), will depend on the beam vergence of the output beam 1010. In this way, increasing the divergence of the output beam 1010 will increase the beam vergence with which the emission beam converges.

[0219] Figure 10B A second variation of the transmit architecture 1050 is shown having a beamformer 1052 and a collimated transmit optical subassembly 1054. The collimated transmit optical subassembly 1054 is Figure 10B 1054 as including a single lens 1056, but it should be understood that other variations of the collimated transmit optics subassembly 1054 may include multiple lens elements. Lens 1056 and any additional lenses of the collimated transmit optics subassembly 1054 may be configured as a one-dimensional lens (such as a cylindrical lens). Typically, the collimated transmit optics subassembly 1054 has a focal length and will collimate light received from a distance corresponding to the focal length.

[0220] The beam generator 1052 is configured to generate beams in a first dimension (e.g., using Figure 10B The collimated transmit optical subassembly 1054 is configured to receive the output beam 1060 and shape the output beam 1060 to generate a transmit beam 1062 that converges in a first dimension. When the transmit architecture 1050 is incorporated into a system having a sampling interface (e.g., in Figure 10B , when in an optical measurement system having a transmit site 1008 (shown in FIG. 1 ), the emission light beam 1062 can project a projected emission light beam 1064 into a transition region 1066 in a sample being measured that is positioned in contact with the transmit site 1008. As discussed in more detail herein, the transition region 1066 represents a point where a converging portion 1064a (e.g., converging in a first dimension) of the projected emission light beam 1064 leaving the transmit site 1008 changes to a diverging portion 1064b (e.g., diverging in the first dimension) of the projected emission light beam 1064.

[0221] To project the projected emission light beam 1064 to the transition region 1066, the collimated transmit optics subassembly 1054 is configured to collimate light exiting the emission surface 1090 of the beamformer 1002 in a first dimension to the transition region 1016. Specifically, the collimated transmit optics subassembly 1054 generates a plurality of collimated light beams 1070a-1070b that collectively form the projected emission light beam 1064. Specifically, the plurality of collimated light beams 1070a-1070b are projected to intersect at the transition region 1066 of the projected emission light beam 1064. Figure 10B In the illustrated variation, each of the plurality of light ray bundles 1070a-1070b is a parallel light ray bundle such that the individual light rays within each bundle are parallel.

[0222] The individual rays of each collimated light bundle are emitted from a different point on the emitting surface 1090 of the beam generator 1052 (e.g., the surface of a diffuser that forms the output beam 1010, the surface of a photonic integrated circuit that forms the output beam 1010, etc.). The rays emitted from a given point on the emitting surface 1090 are at least partially collimated in a first dimension by the collimated transmission optics subassembly 1054 to form a corresponding light bundle. For example, at Figure 10B 1070a and a second light beam 1070b. The first light beam 1070a includes light (represented by rays 1074a-1074c) emitted from a first point 1072 on the emitting surface 1090 of the beamformer 1052. The rays 1074a-1074c exit the first point 1072 at a plurality of different angles but are collimated by the collimating transmit optics subassembly 1054 to form the first light beam 1070a. Similarly, the second light beam 1070b includes light (represented by rays 1078a-1078c) emitted from a second point 1076 on the emitting surface 1090 of the beamformer 1052. The rays 1078a-1078c exit the second point 1076 at a plurality of different angles but are collimated by the collimating transmit optics subassembly 1054 to form the second light beam 1070b.

[0223] Although individual photons may not follow the trajectory of projected emission light beam 1064, each of the ray bundles 1070a-1070b is projected so as to arrive at transition region 1066 at a different angle of incidence, such that the ray bundles 1070a-1070b are projected to intersect at transition region 1066. Specifically, each point in transition region 1066 receives light from each of the plurality of ray bundles 1070a-1070b corresponding to a different emission angle from the surface of beamformer 1052. For example, first point 1080a in transition region 1066 receives all of the light rays from output beam 1060 that exit emission surface 1090 of beamformer 1052 at a first angle (e.g., light rays 1074a emitted from first point 1072 of emission surface 1090 at the first angle and light rays 1078a emitted from second point 1076 of emission surface 1090 at the first angle). Similarly, a second point 1080b in the transition region 1066 receives all light rays from the output beam 1060 that exit the emitting surface 1090 of the beam generator 1052 at the second angle (e.g., light rays 1074b emitted from the first point 1072 of the emitting surface 1090 at the second angle and light rays 1078b emitted from the second point 1076 of the emitting surface 1090 at the second angle).

[0224] In this manner, the beam width of emission beam 1062 in the first dimension, and thus the corresponding beam width of projected emission beam 1064 in the first dimension (e.g., at transition region 1066), will depend on the beam vergence of output beam 1060 in the first dimension. In other words, increasing the beam vergence of output beam 1060 in the first dimension will increase the beam width of projected emission beam 1064 at transition region 1066. Conversely, the beam vergence of emission beam 1062 in the first dimension, and thus the corresponding beam vergence of projected emission beam 1064 in the first dimension (e.g., at transition region 1066), will depend on the beam width of output beam 1010 in the first dimension. In this manner, increasing the size of output beam 1010 in the first dimension will increase the beam vergence with which emission beam 1062 converges in that dimension. Overall, this can improve the wavelength dependence associated with the beam size of emission beam 1062, as described in greater detail herein.

[0225] The emission surface 1090 of the beam generator 1052 can be positioned at a first distance (represented by line 1082) from the collimated transmit optics subassembly 1054, which will result in the transition region 1066 being positioned at a second distance (represented by line 1084) from the collimated transmit optics subassembly 1054 when the emission beam 1062 is emitted into the target sample, as described herein. The relative placement of the emission surface 1090 with respect to the collimated transmit optics subassembly 1054 and the focal length of the collimated transmit optics subassembly 1054 can be adjusted to change one or more parameters of the emission beam 1062.

[0226] For example, Figure 11A A variation of the transmit architecture 1100 is shown having a beamformer 1102 and a collimated transmit optical subassembly 1104. The collimated transmit optical subassembly 1104 is Figure 11A 1106, but it should be understood that the collimated transmission optical subassembly 1104 can be arranged in any manner (such as relative to Figure 10B The sending architecture 1050 is configured in the manner described. Figure 11A In the variation shown, the beam generator 1102 includes a diffuser 1103. The diffuser 1103 is positioned to receive an input beam 1105 (which may be Figure 11A When the input beam 1105 is incident on the back surface of the diffuser 1103, the diffuser 1103 will generate a beam in at least one dimension (e.g., using Figure 11A , along the first dimension of the XZ plane). Thus, the front surface of the diffuser 1103 acts as an emitting surface 1109 of the beam generator 1102, from which the output beam 1110 is emitted.

[0227] The collimated transmit optical subassembly 1104 is positioned to receive the output beam 1110 and shape the output beam 1110 to form a transmitted beam 1112. Specifically, the transmitted beam 1112 includes a plurality of light beam bundles that are projected (e.g., via a projected transmitted beam 1114 projected from a transmit site 1108 of an optical measurement system as described herein) to intersect at a transition region 1116, such as with respect to Figure 10B The sending architecture 1050 is described in more detail. Figure 11A In the illustrated variation, the emitting surface 1109 of the beam generator 1102 is positioned at a telecentric position relative to the collimated transmit optics subassembly 1104 (e.g., the emitting surface 1109 is placed at a distance d1 corresponding to the focal length of the collimated transmit optics subassembly 1104). In this case, the transmitted light beam 1112 is formed by a plurality of parallel light beam bundles that are projected to intersect at a transition region 1116.

[0228] In some variations, the beam generator 1002 may be configured such that the angular content of the output beam 1110 is constant across the output beam 1110 in a first dimension. In other words, at each point on the emitting surface 1109, the output beam 1110 includes an angular range in the first dimension centered about the central ray (e.g., an angular range of ±15 degrees relative to the central ray). When the central rays are all parallel, such as Figure 11A As shown, the output beam 1110 can have the same angular content across the emitting surface 1109. For example, if the input beam 1105 is collimated along a first dimension, each ray incident on the diffuser 1103 will generate a set of rays at a corresponding location on the emitting surface 1109, the set of rays having a common range of emission angles around the corresponding central ray in the first dimension. Collectively, the central rays are parallel across the emitting surface 1109, thereby providing output beams 1110 with spatially independent angular content.

[0229] In these cases, the transition region 1116 will be positioned at a second distance d2 from the collimated transmission optical subassembly 1104 (when taking into account any changes in refractive index between the transmission site 1108 and the sample being measured), and this second distance d2 corresponds to the focal length of the collimated transmission optical subassembly 1104.

[0230] Conversely, if the input beam 1105 converges or diverges in a first dimension upon reaching the diffuser 1103, there will be a position-dependent range of emission angles on the emission surface 1109 of the beam generator 1102 in the first dimension. This can change the distance at which the transition region 1116 is located within the sample being measured (e.g., a target sample as described herein). For example, if the input beam 1105 converges in a first dimension upon reaching the diffuser 1103, the angles emitted by the peripheral portion of the output beam 1110 can be biased toward the center of the output beam 1110 in the first dimension. In other words, the central ray at the emission surface 1109 can be angled toward the center of the output beam 1110 in the first dimension. The central ray can have progressively steeper angles (e.g., higher deviations from normal incidence) as it moves from the center of the output beam 1110 to the periphery of the output beam 1110 along the first dimension.

[0231] In these cases, the transition region 1116 will be positioned at a second distance d2 from the collimated transmit optics subassembly 1104 (when accounting for any change in refractive index between the transmit site 1108 and the sample being measured) that is less than the focal length of the collimated transmit optics subassembly 1104. Thus, reducing the focal length of the collimated transmit optics subassembly 1104 and / or increasing the convergence of the input beam 1105 can bring the transition region 1116 closer to the transmit site 1108, which can be used to position the transition region 1116 at a specific location in the target sample (e.g., at a sample region that is independently angled for one or more measurement channels, such as described herein). In other cases, the input beam 1105 can diverge, in which case the transition region 1116 will be positioned at a second distance d2 that is greater than the focal length of the collimated transmit optics subassembly 1104.

[0232] exist Figure 11A In the variation shown, the beamwidth of the output beam 1110 in the first dimension depends on the corresponding beamwidth h of the input beam 1105 in the first dimension, and the beam divergence half-angle θ of the output beam 1110 depends on the diffusing properties of the diffuser 1103. Figure 10B As discussed in more detail in the transmit architecture 1050 of FIG. 1 , the beamwidth h′ of the projected transmit light beam 1114 in the first dimension at the transition region 1116 depends on the beam divergence half-angle θ of the output light beam 1110 in the first dimension. The angular divergence ω of the projected transmit light beam 1114 in the first dimension at the transition region 1116 depends on the beamwidth h of the input light beam 1105 in the first dimension.

[0233] When the emitting surface 1109 of the beamformer 1102 is positioned at a telecentric position relative to the collimated transmit optical subassembly 1104 (and the bundles of rays forming the transmit light beam 1112 are each bundles of parallel rays), each point in the transition region 1116 is projected to receive light having the same angular content. Specifically, each point in the transition region 1116 is projected to receive light having an angular range (e.g., ω degrees) in a first dimension centered about the corresponding central ray. Collectively, the central rays (for example, at Figure 11A It is shown that the three central light rays 1120a-1120c) are parallel.

[0234] On the contrary, Figure 11BAnother variation of a transmit architecture 1150 is shown that is configured identically to transmit architecture 1100 (with like components labeled identically), except that the emitting surface 1109 of the beamformer 1102 is positioned at a hyper-telecentric position relative to the collimated transmit optics subassembly 1104. Specifically, the emitting surface 1109 is positioned at a distance d3 from the collimated transmit optics subassembly 1104, where d3 is greater than the focal length of the collimated transmit optics subassembly 1104. In these cases, the collimated transmit optics subassembly 1104 will generate a beam in a first dimension (e.g., using a beamformer 1102) based on the light emitted from each location on the emitting surface 1109. Figure 11B , along the XZ plane) of the Cartesian coordinate system depicted in FIG. 1 . For example, a first converging light beam (represented by light rays 1152a-1152c) is formed by light (represented by light rays 1156a-1156c) emitted at a first point 1154 on the emission surface 1109. Thus, the collimated transmit optics subassembly 1104 forms an emission beam 1162 composed of a plurality of converging light beams based on the output beam 1110. Each converging light beam exits the collimated transmit optics subassembly 1104 at a different angle, such that the converging light beams are projected (e.g., via a projected emission beam 1164 projected from a transmit site 1108 of an optical measurement system as described herein) to intersect at the transition region 1116.

[0235] Thus, each point of the transition region 1116 is projected to receive light having a different angular content. Specifically, each point of the transition region 1116 is projected to receive light having an angular range (e.g., ω degrees) centered about the corresponding central ray in a first dimension. Collectively, the central ray (for illustration, at Figure 11B 1162 , three central rays 1152 a - 1152 c ) corresponding to rays of the first converging bundle of rays are shown converging at a beam divergence half-angle β. In this manner, rays at the periphery of the emitted light beam 1162 are preferably angled toward the center of the emitted light beam 1162 in a first dimension.

[0236] The emitting surface 1109 of the beamformer 1102 is positioned at a hyper-telecentric position relative to the collimated transmit optics subassembly 1104 (such as Figure 11B The transmit architecture 1150) can help balance the collection efficiency of the transmitted beam 1162 across one or more measurement channels. Figure 9A 、 Figure 9B and Figures 9C to 9D Any of the transmitting architectures 902, 932, and 962 of the optical measurement systems 900, 930, and 960, respectively, may be configured to communicate with Figure 11B The sending architecture 1150 is the same as that of Figures 9C to 9DAs an example of the optical measurement system 960, the transmitting optical subassembly 984 of the optical measurement system 960 can be configured as a collimated transmitting optical subassembly.

[0237] If the emitting surface of beamformer 980 is positioned at a telecentric position relative to transmit optics subassembly 984, there may be slight differences in the median path length (and thus collection efficiency) across transition region 976 for light measured by a given measurement channel of optical measurement system 960. For a first measurement channel (e.g., light measured by first detector element 966a), the light projected to pass through the leftmost portion of transition region 976 along a first dimension (e.g., corresponding to Figure 11A Light at point 1122a in the transition region 1116 shown will have a greater optical gain than light projected to pass through the center of the transition region 976 along the first dimension (e.g., corresponding to Figure 11A Similarly, the light projected to pass through the rightmost portion of the transition region 976 along the first dimension (e.g., corresponding to point 1122b in the transition region 1116) has a short median path length. Figure 11A 11. The first measurement channel will preferentially receive light projected through the leftmost portion of transition region 976 along the first dimension, while the fourth measurement channel will preferentially receive light projected through the rightmost portion of transition region 976 along the first dimension.

[0238] Positioning the emitting surface of the beamformer 980 at a hyper-telecentric position relative to the transmit optics subassembly 984 balances the median path length across the transition region 975. In these cases, the leftmost portion of the beamformer 980 projected to pass through the transition region 975 (e.g., corresponding to Figure 11B 1166) will be angled slightly away from the first detector element 966a in the first dimension. This can increase the median path length of light measured by the first measurement channel for light projected to pass through the leftmost portion of the transition region 975. Similarly, light projected to pass through the rightmost portion of the transition region 975 (e.g., corresponding to Figure 11B1170c in the transition region 1166 shown will be angled slightly in the first dimension toward the first detector element 966a. This can reduce the median path length of light measured by the first measurement channel for light projected to pass through the leftmost portion of the transition region 975. Depending on the choice of the convergence half-angle β of the converging light beam, the emitted light beam 971 can be configured so that the light measured by the first measurement channel has the same median path length regardless of whether the measured light is projected to have passed through the leftmost portion, the rightmost portion, or the center of the transition region 975 (e.g., corresponding to Figure 11B Point 1170b in the transition region 1166 is shown).

[0239] Return to Figure 11B The configuration of output beam 1110 can at least partially control the distance between collimated transmit optics subassembly 1104 and transition region 1166 of projected emission beam 1164. When beamformer 1002 is configured such that the angular content of output beam 1110 is constant across output beam 1110 in a first dimension, transition region 1166 will be positioned at a distance d4 from collimated transmit optics subassembly 1104, corresponding to the focal length of collimated transmit optics subassembly 1104. Conversely, if output beam 1110 has a range of emission angles that are dependent on its position on emission surface 1109 of beamformer 1102 in the first dimension, distance d4 will differ from the focal length of collimated transmit optics subassembly 1104. For example, if input beam 1105 is converging, distance d4 will be less than the focal length of collimated transmit optics subassembly 1104. Conversely, if input beam 1105 is diverging, distance d4 will be greater than the focal length of collimated transmit optics subassembly 1104.

[0240] While the transmit architecture of the optical measurement system described herein utilizes a beam generator to generate an output beam, it should be understood that the beam generator may include any number and combination of components necessary to generate the output beam, as will be readily understood by one of ordinary skill in the art. Typically, a beam generator includes one or more light sources that generate light. In some cases, a beam generator includes one or more light-modifying components (e.g., lenses, mirrors, beam splitters, polarizers, etc.) that shape and / or redirect the light generated by the one or more light sources to form an output beam.

[0241] For example, Figure 12A block diagram of an example beam generator 1200 that can be used with the optical measurement systems described herein to generate an output beam 1220 is shown. As shown, the beam generator 1200 can include a photonic integrated circuit 1202, an optical unit 1204, and a diffuser 1206. The photonic integrated circuit 1202 is configured to emit a first light beam 1230. For example, the photonic integrated circuit 1202 can include a light source unit 1208, such as described herein, that generates light used to form the first light beam 1230. Specifically, at least a portion of the light generated by the light source unit 1208 can be routed within the photonic integrated circuit 1202 (e.g., using one or more waveguides) to a first set of output couplers (e.g., a single output coupler or multiple output couplers). The light can exit the photonic integrated circuit 1202 via the first set of output couplers to form the first light beam 1230.

[0242] Diffuser 1206 is configured to receive input light beam 1240 and generate output light beam 1220 therefrom. Specifically, diffuser 1206 can be any optical diffuser that diffuses incident light. In some variations, diffuser 1206 can be a transmissive diffuser, such that output light beam 1220 is formed when input light beam 1240 passes through diffuser 1206. Specifically, as light passes through diffuser 1206, it will be scattered and / or refracted, depending on the configuration of diffuser 1206. Light passing through a given position of the diffuser will generate diffused light having an angular spread in multiple dimensions (referred to herein as the "diffuser angle"). Therefore, the beam divergence of output light beam 1220 may depend on the diffuser angle. For example, in some variations, the diffuser angle may have a half-angle of at least five degrees when measured in air (e.g., light passing through the diffuser will be diffused by at least five degrees along one or more dimensions relative to the central beam when measured in air), which may cause the diffuser 1206 to generate an output beam 1220 having a beam divergence half-angle of at least five degrees (when measured in air) in at least one dimension. In other variations, the diffuser angle may have a half-angle of at least fifteen degrees when measured in air, which may cause the diffuser 1206 to generate an output beam 1220 having a beam divergence half-angle of at least fifteen degrees (when measured in air) in at least one dimension.

[0243] In some variations, the diffuser 1206 may be positioned to receive light directly from the photonic integrated circuit 1202, in which case the first light beam 1230 may serve as the input light beam 1240 to the diffuser 1206. Alternatively, the optical elements 1204 may act together to shape and / or redirect at least a portion of the first light beam 1230 to form the input light beam 1240. Figure 12In the illustrated variation, optical unit 1204 is configured to perform collimation in one or more dimensions (e.g., fast-axis collimation 1210 and slow-axis collimation 1212), beam steering 1214, and beam splitting 1216, but it will be appreciated that optical unit 1204 may alternatively be configured to perform any suitable combination of these functions. Typically, optical unit 1204 includes one or more light-modifying components, such as one or more lenses, such as those described herein, that collectively perform the functions of optical unit 1204.

[0244] 13A to 13F Depicts variations of beamformers that can be used with the transmit architecture described herein. Specifically, Figure 13A A top view of a transmit architecture 1300 that can be used with the optical measurement system described herein is depicted. The transmit architecture 1300 includes a beam generator 1302 and a transmit optical subassembly 1304. The beam generator 1302 is configured to generate an output beam 1306. The transmit optical subassembly 1304 is configured to receive the output beam 1306 and shape it to form an emission beam 1307. The emission beam 1307 can be emitted from the optical measurement system via a transmit site 1308 of a sampling interface such that the emission beam 1307 projects a projected emission beam 1309 into a target sample 1310 positioned in contact with the transmit site 1308.

[0245] The emission beam 1307 (and thus the projected emission beam 1309 when the emission beam 1307 is emitted into the target sample 1310) may be as described herein with respect to Figures 3A to 3B and 9A to 9D For example, the emission beam 1307 may be converging in a first dimension such that it projects a projected emission beam 1309 that transitions between a converging portion and a diverging portion in the first dimension. In these cases, Figure 13A A second dimension perpendicular to the first dimension of the emitted light beam 1307 is depicted (e.g., along the YZ plane of the Cartesian coordinate system as shown), and line 1312 represents the transition region. Figure 13A In the illustrated variation, emission beam 1307 diverges in a second dimension (e.g., beam generator 1302 generates an output beam 1306 that diverges in the second dimension, and transmit optics subassembly 1304 is configured as a one-dimensional lens set that does not alter the divergence in the second dimension when generating emission beam 1307). Thus, emission beam 1307 projects a projected emission beam 1309 that diverges in the second dimension.

[0246] To generate the output beam 1306, the beam generator 1302 includes a photonic integrated circuit 1314, an optical unit 1316, and a diffuser 1318. The photonic integrated circuit 1314 includes a set of output couplers, each of which is configured to emit a corresponding light beam from the photonic integrated circuit 1314. Specifically, the photonic integrated circuit 1314 includes one or more light sources (not shown) configured to generate light emitted via the set of output couplers. Figure 13A In the illustrated variation, the photonic integrated circuit 1314 includes a plurality of output couplers 1320a-1320c configured to emit a plurality of individual light beams 1322a-1322c. The individual light beams 1322a-1322c at least partially overlap and collectively form an input light beam 1324. The input light beam 1324 is received by a diffuser 1318, which diffuses the input light beam 1324 to generate an output light beam 1306.

[0247] The plurality of output couplers 1320a-1320c may be configured in any suitable manner and may include edge couplers, vertical output couplers, etc. For example, in Figure 13A In the illustrated variation, each of the plurality of output couplers 1320a-1320c is configured as an edge coupler such that a corresponding portion of a side surface of the photonic integrated circuit 1314 serves as an output facet from which a corresponding one of the plurality of individual light beams 1322a-1322c can be emitted. For example, each of the plurality of output couplers 1320a-1320c includes a portion of a side surface of the photonic integrated circuit 1314 that is shaped to form an on-chip lens, such as described in U.S. Patent Publication No. US2023 / 0089758A1, entitled “Light Output Devices and Light Outputting Methods for Optical Systems,” the contents of which are incorporated herein by reference in their entirety.

[0248] Each of the plurality of individual light beams 1322a-1322c may diverge differently in different dimensions upon exiting the photonic integrated circuit 1314. For example, upon exiting the photonic integrated circuit 1314, the plurality of individual light beams 1322a-1322c may have a higher divergence in a first dimension (hereinafter referred to as the "fast axis") than in a second dimension perpendicular to the first dimension (hereinafter referred to as the "slow axis"). Thus, the resulting input light beam 1324 may have a fast axis and a slow axis upon exiting the photonic integrated circuit 1314. In variations in which the transmit architecture 1300 is used to generate a transmit light beam 1307 that is wider in one dimension, such as with respect to Figure 3A and Figure 3BThe input beam 1324 can also be wider in one dimension as described for the transmit architecture 302. In some of these variations, the input beam 1324 is wider along the slow axis than along the fast axis.

[0249] In some variations, the optical unit 1316 may be configured to collimate the input light beam 1324 at least partially along the fast axis and the slow axis. Figure 13A In the illustrated variation, the optical unit 1316 includes a fast-axis collimating lens 1326 configured to at least partially collimate the input light beam 1324 along its fast axis and a slow-axis collimating lens 1328 configured to at least partially collimate the input light beam 1324 along its slow axis. Figure 13A As shown, the slow axis collimating lens 1328 collimates each of the plurality of individual light beams 1322a-1322c along the second dimension. Alternatively, the slow axis collimating lens 1328 may be positioned relative to the photonic integrated circuit 1314 such that the collimated light beams 1322a-1322c intersect at the diffuser 1318. In these cases, the input light beam 1324 is collimated along the second dimension (e.g., Figure 13A The size of the input beam 1324 as it enters the diffuser 1318 will be independent of the number of output couplers 1320a-1320c and the number of emitted individual light beams 1322a-1322c. Additionally, to the extent that different ones of the plurality of output couplers 1320a-1320c emit light beams 1322a-1322c having different phases (e.g., using one or more phase shifters to alter the relative phases of the light beams 1322a-1322c), the size of the input light beam 1324 along the second dimension as it enters the diffuser 1318 will be independent of the relative phases of the individual light beams 1322a-1322c. Consequently, the size of the output beam 1306 generated by the diffuser 1318 will also be independent of the number and relative phases of the plurality of individual light beams 1322a-1322c.

[0250] 13B to 13F Shown Figure 13A Side views of different variations of the transmit architecture 1300. Figure 11A and Figure 11B As discussed, the vergence angle of the input light beam 1324 as it reaches the diffuser 1318 can affect the placement of the transition region 1312 of the projected emission light beam 1309. For example, Figure 13B A side view of a first variation of a transmit architecture 1330 is shown. The transmit architecture 1330 can be configured identically to the transmit architecture 1300 (with identical components labeled identically), and can be configured such that the input beam 1324 is collimated in a first dimension (e.g., along Figure 13B XZ plane shown).

[0251] The input light beam 1324 may diverge along a first dimension (e.g., along the fast axis) as it exits the photonic integrated circuit 1314. Figure 13B In the illustrated variation, the fast axis collimating lens 1326 fully collimates the input beam 1324 in a first dimension (e.g., along the fast axis). The slow axis collimating lens 1328 does not alter the input beam 1324 in the first dimension, such that the input beam 1324 is collimated when it reaches the diffuser 1318. Figure 13B 13), the transmit optics subassembly 1304 will use the input beam 1324 to generate a transmit beam 1307 that is convergent in a first dimension. Additionally, the transmit beam 1307 will project a projected transmit beam 1309 having a transition region located at a distance corresponding to the focal length of the transmit optics subassembly 1304, such as described in more detail herein.

[0252] When the optical measurement system described herein utilizes separate measurements of different wavelengths as part of a spectral measurement, the transmit architecture described herein can be used to generate an emission beam formed of different wavelengths at different times (and / or of multiple wavelengths at the same time). In some cases, changing the wavelength of the emission beam can change one or more properties of the emission beam. For example, when the photonic integrated circuit 1314 of the transmit architecture 1330 emits a signal such as Figure 13B As shown for input beam 1324, the divergence of input beam 1324 in a first dimension (e.g., the fast axis) can depend on the wavelength of light emitted by photonic integrated circuit 1314. Light with longer wavelengths can have a larger diffraction angle than light with shorter wavelengths. After collimation by fast-axis collimating lens 1326, the beamwidth of input beam 1324 in the first dimension can depend on the wavelength of the light (e.g., longer wavelengths will have a wider beamwidth in the first dimension).

[0253] When the transmitting optical subassembly 1304 is configured as Figure 13B When collimating the transmit optical subassembly as shown, these wavelength-dependent changes in the beam width of the input light beam 1324 will not change the size of the transition region 1312 in the first dimension. Figure 11A and Figure 11B As discussed, the beamwidth of the projected emission light beam 1309 in the first dimension at the transition region 1312 depends on the beam divergence half-angle of the output light beam 1306 in the first dimension. The beam divergence half-angle of the output light beam 1306 is determined by the properties of the diffuser 1318, not by the size of the input light beam 1324. Conversely, wavelength-dependent changes in the beamwidth of the input light beam 1324 can affect the angular divergence of the projected emission light beam 1309 in the first dimension at the transition region 1312.

[0254] exist Figure 13B In the illustrated variation, the optical unit 1316 can further include a beam splitter 1332 positioned between the slow-axis collimating lens 1328 and the diffuser 1318. The beam splitter 1332 is configured to separate a portion of the input beam 1324 into a reference beam 1334. At least a portion of the reference beam 1334 can be directed to a reference detector 1336, which can measure the intensity of the reference beam 1334. Measurements from the reference detector 1336 can be used by the optical measurement system described herein (e.g., using a controller) to resolve fluctuations in the intensity of the reference beam 1334 (which can be representative of the power of the emission beam 1307).

[0255] Figure 13C FIG2 shows a side view of another variation of a transmit architecture 1340. The transmit architecture 1340 may be configured to Figure 13B The transmit architecture 1330 is identical to that of FIG. 1 (where like components are labeled like), and may also be configured such that the input beam 1324 is collimated in a first dimension (e.g., along Figure 13C XZ plane shown). Figure 13C In a variation of FIG. 1 , the fast-axis collimating lens 1326 partially collimates the input beam 1324 in the first dimension, such that the input beam 1324 remains divergent in the first dimension after exiting the fast-axis collimating lens 1326. The slow-axis collimating lens 1328 can also be used to collimate the input beam 1324 in the first dimension (e.g., the slow-axis collimating lens 1328 can be configured as a cross-cylindrical lens), such that the input beam 1324 is collimated in the first dimension after exiting the slow-axis collimating lens 1328. This arrangement can make the transmit architecture 1340 less sensitive to misalignment of the fast-axis collimating lens 1326.

[0256] In some of these variations, the slow axis collimating lens 1328 and the beam splitter 1332 can be positioned and configured to image the fast axis collimating lens 1326 onto the reference detector 1336. In these cases, vertical misalignment of the fast axis collimating lens 1326 relative to the photonic integrated circuit 1314 (e.g., along the direction of the reference detector 1336) is not required. Figure 13C The x-axis shown) can still cause reference beam 1334 to be incident on the same portion of reference detector 1336. In this way, measurements performed by reference detector 1336 can be less sensitive to misalignment of fast axis collimating lens 1326.

[0257] Figure 13D FIG2 shows a side view of another variation of a transmit architecture 1350. The transmit architecture 1350 may be configured to Figure 13CThe transmit architecture 1340 is identical to the transmit architecture 1340 of FIG. 1 (where like components are labeled like), except that the beamformer 1302 is configured to generate a beam in a first dimension (e.g., along Figure 13D The XZ plane shown) diverges the input beam 1324. Figure 13D In a variation of FIG1 , the fast-axis collimating lens 1326 partially collimates the input beam 1324 in the first dimension, such that the input beam 1324 remains divergent after exiting the fast-axis collimating lens 1326. The slow-axis collimating lens 1328 focuses the input beam 1324 in the first dimension to a focal point 1352 between the slow-axis collimating lens 1328 and the diffuser 1318. When the input beam 1324 passes through the focal point 1352, the input beam 1324 transitions from a converging beam in the first dimension to a diverging beam in the first dimension. Thus, the input beam 1324 will diverge in the first dimension when it enters the diffuser 1318.

[0258] Figure 13E 13 shows a side view of another variation of a transmit architecture 1360 configured to generate an input beam 1324 that diverges in a first dimension as it enters a diffuser 1318. Specifically, the transmit architecture 1360 can be configured with Figure 13D The transmit architecture 1350 is identical to that of FIG1 (where like components are labeled like), except that the slow-axis collimating lens 1328 does not alter the input beam 1324 in the first dimension. In this manner, the input beam 1324 (which is partially collimated, but still diverging after passing through the fast-axis collimating lens 1326) will continue to diverge when it reaches the diffuser 1318.

[0259] Figure 13F FIG2 shows a side view of another variation of a transmit architecture 1370. The transmit architecture 1370 may be configured with Figure 13C The transmit architecture 1340 is identical to the transmit architecture 1340 of FIG. 1 (where like components are labeled like), except that the beamformer 1302 is configured to generate a beam in a first dimension (e.g., along Figure 13F The XZ plane shown) converges the input beam 1324. Figure 13F In a variation of FIG1 , a fast-axis collimating lens 1326 partially collimates the input beam 1324 in a first dimension, such that the input beam 1324 remains divergent after exiting the fast-axis collimating lens 1326. A slow-axis collimating lens 1328 focuses the input beam 1324 in the first dimension to a focal point (not shown) located outside the diffuser 1318. The input beam 1324 will reach the diffuser 1318 before the focal point, and thus the input beam 1324 will be converging in the first dimension as it enters the diffuser 1318.

[0260] Collection architecture for use in optical measurement systems

[0261] The optical measurement systems described herein can use a range of possible collection architectures to collect light and direct it to one or more detector elements. Typically, such as with respect to Figure 5A 、 Figure 5B and Figures 7 to 9D As described, the collection architecture includes one or more sets of detector elements and one or more collection optical subassemblies, each of which is configured to collect a set of return beams and direct the set of return beams to a corresponding set of detector elements. Figures 14A to 18C An example of a collection architecture is described. It should be understood that a send architecture can be used as an example herein with respect to Figures 1A to 9D Part of the optical measurement system described (e.g., can be used to collect any of the return beams described with respect to these figures), or can be used as part of any other optical measurement system as described herein where collection of return beams is desired.

[0262] When the collection architecture includes a collection optics subassembly configured to direct light to a plurality of detector elements (e.g., such as described above with respect to Figure 5B and Figures 9B to 9D As used herein, the "sampling depth distribution" of a measurement channel refers to a probability distribution that represents the likelihood that a photon of light measured by the measurement channel (i.e., light introduced into the sample from the optical measurement system and collected by the detector elements of the measurement channel) will penetrate to a specific sample depth in a sample having certain properties (e.g., a target sample as described herein). As used herein, the "median sampling depth" of a sampling depth distribution refers to a sampling depth that represents the 50% value of the cumulative distribution function based on the sampling depth distribution. In other words, there is a 50% probability that a given photon measured by the measurement channel will reach a sampling depth in the sample that is shorter than the median sampling depth.

[0263] In situations where the sample being measured has different sample characteristics and / or sample properties as a function of sample depth, it may be advantageous to consider the sampling depth distribution of the light collected by the measurement channel. For example, the sample being measured may include multiple layers, each layer having different sample characteristics and / or sample properties. In these situations, it may be desirable to understand and / or control the depth to which the measurement light has penetrated the sample being measured.

[0264] Thus, the collection architecture described herein can be configured to adjust the relative sampling depth distribution and path length distribution of light measured by different measurement channels. For example, Figure 14AAn example of a collection architecture 1400 that can be used with the optical measurement system described herein is shown. Specifically, the collection architecture 1400 includes a collection optics subassembly 1402 and a plurality of detector elements 1404a-1404c that define a plurality of measurement channels of the optical measurement system. The collection optics subassembly 1402 is configured to collect a plurality of return beams 1406a-1406c from a sample being measured through a collection site 1410 of a sampling interface (e.g., when a transmit architecture of the optical measurement system (such as those described herein) transmits light into the sample being measured) and is configured to direct each of the return beams 1406a-1406c to a corresponding detector element of the plurality of detector elements 1404a-1404c.

[0265] A plurality of return beams 1406a-1406c are projected to emanate from a plurality of projected return beams 1408a-1408c in the sample being measured such that each return beam is projected to emanate from a corresponding projected return beam. Specifically, a first return beam 1406a is projected to emanate from a first projected return beam 1408a and is measured by a first detector element 1404a, a second return beam 1406b is projected to emanate from a second projected return beam 1408b and is measured by a second detector element 1404b, and a third return beam 1406c is projected to emanate from a third projected return beam 1408c and is measured by a third detector element 1404c. Each of the return beams 1406a-1406c and its corresponding projected return beam may have a configuration as described above with respect to Figure 5A and Figure 5B Any characteristics described for the return beam 504 and the projected return beam 506.

[0266] exist Figure 14A In the illustrated variation, each of the return beams 1406a-1406c is transmitted along a common first dimension (e.g., along Figure 14A In this manner, each of the plurality of return beams 1406a-1406c is projected to emanate from a projected return beam having a diverging portion along a first dimension as it enters the sampling interface and transitioning from a converging portion at a corresponding collection transition region (at Figure 14AOnly the diverging portions of the return beams 1406a-1406c are shown in FIG. 1 ). Thus, the plurality of return beams 1406a-1406c are associated with a plurality of collection transition regions 1412a-1412c (e.g., the first projected return beam 1408a has a first collection transition region 1412a, the second projected return beam 1408b has a second collection transition region 1412b, and the third projected return beam 1408c has a third collection transition region 1412c). In some variations, such as with respect to Figures 5A to 5B and Figures 8 to 9D As described in more detail in the optical measurement system of FIG. 14 , when the collection architecture 1400 is used to collect light from a target sample, some or all of these transition regions 1412 a - 1412 c may be positioned at angle-independent sample regions for corresponding measurement channels.

[0267] Depending on the configuration of the emission beam, the measurement channel formed by the multiple detector elements 1404a-1404c can measure light with different path length distributions and different sampling depth distributions. Figure 14B An example graph 1430 is shown which represents the performance of the collection architecture 1400 when incorporated as Figure 9B Collection architecture 934 of optical measurement system 930 depicts the range of path lengths and sampling depths of light collected by each measurement channel of collection architecture 1400. Specifically, graph 1430 includes a first distribution 1432a, which represents the range of possible path length and sampling depth combinations (with a minimum threshold probability) for light measured by first detector element 1404a; a second distribution 1432b, which represents the range of possible path length and sampling depth combinations (with a minimum threshold probability) for light measured by second detector element 1404b; and a third distribution 1432c, which represents the range of possible path length and sampling depth combinations (with a minimum threshold probability) for light measured by third detector element 1404c. As shown, the light measured by first detector element 1404a, on average, has a longer optical path length and a deeper sampling depth than the light measured by second detector element 1404b. Similarly, the light measured by second detector element 1404b, on average, has a longer optical path length and a deeper sampling depth than the light measured by third detector element 1404c.

[0268] The design of the collection optics subassembly 1402 can at least partially control the relative sampling depth distribution of the measurement channels associated with the plurality of detector elements 1404a-1404c. Figure 14A, collection optics subassembly 14042 includes an imaging lens 1420, a relay lens 1422, and an aperture 1424 positioned between imaging lens 1420 and relay lens 1422. Collection optics subassembly 1402 is configured to receive and shape the plurality of return beams 1406a-1406c to form a corresponding plurality of measurement beams 1414a-1414c, each of which is measured by a corresponding detector element of the plurality of detector elements 1404a-1404c.

[0269] exist Figure 14A In the illustrated variation, aperture 1424 is placed at an object telecentric position in the first dimension, such that collection optics subassembly 1402 acts as an object telecentric lens in the first dimension. In these cases, each of return beams 1406a-1406c has the same angular content in the first dimension (e.g., the same beam direction and beam vergence) when it enters collection site 1410, but collects the angular content from different spatial locations on collection site 1410. In this manner, multiple detector elements 1404a-1404c each measure light having the same angular content in the first dimension but projected to emanate from different collection transition regions.

[0270] However, if the aperture 1412 is placed at a non-telecentric position, the multiple return beams 1406a-1406c may have different angular contents. For example, Figure 14C Another variation of a collection architecture 1440 as described herein is shown. The collection architecture 1440 includes a collection optics subassembly 1442 and a plurality of detector elements 1444a-1444c. The collection architecture 1440 is otherwise configured to Figure 14A The collection architecture 1400 is the same as that of FIG. 1 , except that the collection optics subassembly 1442 includes an imaging lens 1420, a relay lens 1422, and an aperture 1424, wherein the aperture 1424 is positioned more telecentric than the object (which is at Figure 14C Line 1458, depicted for comparison, is closer to the sampling interface.

[0271] The collection architecture 1440 is configured to collect a plurality of return beams 1446a-1446c from the collection location 1410. The plurality of return beams 1446a-1446c are projected to emanate from a plurality of projected return beams 1448a-1448c in the measurement sample, wherein the projected return beams 1448a-1448c have a corresponding plurality of collection transition regions 1452a-1452c. The collection optics subassembly 1442 is configured to receive the plurality of return beams 1446a-1446c and shape them to form a corresponding plurality of measurement beams 1454a-1454c, each measurement beam being measured by a corresponding detector element of the plurality of detector elements 1444a-1444c.

[0272] Due to the positioning of aperture 1424, each of the multiple return beams 1446a-1446c has a different angular content. Figure 14A The central rays of the return beams 1406a-1406c in the first dimension may be parallel, while Figure 14C The central rays of the return beams 1446a-1446c in the plurality of return beams 1446a-1446c can converge in a first dimension. Specifically, when the plurality of return beams 1446a-1446c includes three return beams (e.g., the second return beam 1446b is located between the first return beam 1446a and the third return beam 1446c), the central rays of the first and third return beams 1446a, 1446c can be angled toward the central ray of the second return beam 1446b.

[0273] Changing the angular content of the return beams 1446a-1446c can change the relative sampling depth of the collected light projected to travel through the plurality of transition regions 1452a-1452c. Specifically, placing the aperture 1424 closer to the sampling interface than the object telecentric position can increase the difference in median sampling depth between the measurement channels corresponding to the plurality of detector elements 1444a-1444c. For example, Figure 14D An example graph 1460 is shown which represents the performance of the collection architecture 1440 when it is incorporated as Figure 9B The collection architecture 934 of the optical measurement system 930 is a graph showing the range of path lengths and sampling depths of light collected by each measurement channel of the collection architecture 1440. Specifically, the graph 1460 includes a first distribution 1462a representing the range of possible path length and sample depth combinations (having a minimum threshold probability) of light measured by the first detector element 1444a; a second distribution 1462b representing the range of possible path length and sample depth combinations (having a minimum threshold probability) of light measured by the second detector element 1444b; and a third distribution 1462c representing the range of possible path length and sample depth combinations (having a minimum threshold probability) of light measured by the third detector element 1444c.

[0274] The light measured by first detector element 1444a has, on average, a deeper sampling depth than the light measured by second detector element 1444b, but the difference in median sampling depths between first distribution 1462a and second distribution 1462b of curve 1460 is greater than the difference in median sampling depths between first distribution 1432a and second distribution 1432b of curve 1430. Similarly, the light measured by second detector element 1444b has, on average, a longer optical path length and a deeper sampling depth than the light measured by third detector element 1444c, but the difference in median sampling depths between second distribution 1462b and third distribution 1462c of curve 1460 is greater than the difference in median sampling depths between second distribution 1432b and third distribution 1432c of curve 1430. Additionally, where the plurality of transition regions 1452a-1452c are positioned at sample regions in the target sample that are angularly independent for their corresponding measurement channels, the collection architecture 1440 can adjust these relative depth differences without significantly affecting the path length distribution measured by the plurality of detector elements 1444a-1444c. For example, the first, second, and third transition regions 1452a-1452c can be angularly independent for the corresponding first, second, and third measurement channels, respectively, measured by the plurality of detector elements 1444a-1444c.

[0275] Figure 14E Another variation of a collection architecture 1470 as described herein is shown. The collection architecture 1470 includes a collection optics subassembly 1472 and a plurality of detector elements 1474a-1474c. The collection architecture 1470 is otherwise configured to Figure 14A The collection architecture 1400 is the same as that of FIG. 1 , except that the collection optics subassembly 1472 includes an imaging lens 1420, a relay lens 1422, and an aperture 1424, wherein the aperture 1424 is positioned more telecentrically than the object (at Figure 14E Line 1458, depicted for comparison, is further away from the sampling interface.

[0276] The collection architecture 1470 is configured to collect a plurality of return beams 1476a-1476c that enter the collection architecture 1470 at the collection site 1410. The plurality of return beams 1476a-1476c are projected to emanate from a plurality of projected return beams 1478a-1478c in the measurement sample, wherein the projected return beams 1478a-1478c have a corresponding plurality of collection transition regions 1482a-1482c. The collection optics subassembly 1472 is configured to receive the plurality of return beams 1476a-1476c and shape them to form a corresponding plurality of measurement beams 1484a-1484c, each measurement beam being measured by a corresponding detector element in the plurality of detector elements 1474a-1474c.

[0277] In these cases, each of the multiple return beams 1446a-1446c has a different angular content. Figure 14A The central rays of the return beams 1446a-1446c in the first dimension can converge, while Figure 14C The central rays of the return beams 1476a-1476c in the plurality of return beams 1476a-1476c can diverge in a first dimension. Specifically, when the plurality of return beams 1476a-1476c includes three return beams (e.g., the second return beam 1476b is located between the first return beam 1476a and the third return beam 1476c), the central rays of the first and third return beams 1476a, 1476c can be angled away from the central ray of the second return beam 1476b.

[0278] Changing the angular content of the return beams 1476a-1476c in this manner can reduce the difference in median sampling depth between the measurement channels corresponding to the multiple detector elements 1474a-1474c. Figure 14F An example diagram 1490 is shown, which shows that when the collection architecture 1470 is incorporated as Figure 9B The collection architecture 934 of the optical measurement system 930 is a graph showing the range of path lengths and sampling depths of light collected by each measurement channel of the collection architecture 1470. Specifically, the graph 1490 includes a first distribution 1492a representing the range of possible path length and sampling depth combinations (having a minimum threshold probability) of light measured by the first detector element 1474a; a second distribution 1492b representing the range of possible path length and sampling depth combinations (having a minimum threshold probability) of light measured by the second detector element 1474b; and a third distribution 1492c representing the range of possible path length and sampling depth combinations (having a minimum threshold probability) of light measured by the third detector element 1474c.

[0279] exist Figure 14F In the illustrated variation, the light measured by each of the plurality of detector elements 1474a-1474c has approximately the same median sampling depth. For purposes of this application, a plurality of sampling depth profiles (each associated with a corresponding median sampling depth) are considered to be "approximately the same" if the median sampling depths of the plurality of sampling depth profiles are all within 10% (e.g., ±10%) of the average of the median sampling depths. It should be understood that in other cases, there may be differences in the median sampling depths between the first, second, and third distributions 1492a-1492c of plot 1430, but these differences may be smaller than the corresponding differences between the distributions 1432a-1432c of plot 1490.

[0280] Thus, the positioning of the aperture 1424 between the imaging lens 1420 and the relay lens 1422 of the collection optics subassembly can be selected to achieve a desired distribution of median sampling depths for a given set of measurement channels. Additionally, because there may be a tradeoff between collection effectiveness and sampling depth (e.g., the amount of returned light may decrease as a function of sampling depth), this balance may be considered when selecting the aperture 1424 position. In some variations, the collection optics subassembly may include an actuator configured to selectively move the aperture 1424. In these cases, the actuator may selectively move the aperture 1424 at an object telecentric location (e.g., at an object telecentric location). Figure 14A ) and one or more non-object telecentric locations (e.g. Figure 14C and Figure 14E ) as depicted in the figure.

[0281] exist Figures 14A to 14E In the variation shown, different detector elements associated with the collection optics subassembly can measure light having different path length distributions and different sampling depth distributions. In some cases, it may be desirable to configure the collection architecture to measure light having approximately the same path length distribution and different sampling depth distributions using different detector elements. Figure 15A One such variation of a collection architecture as described herein is depicted as 1500. The collection architecture 1500 includes a collection optics subassembly 1502 and a plurality of detector elements 1504a-1504c, wherein the collection optics subassembly 1502 includes a condenser lens 1512. Light passing through the condenser lens 1512 is measured by the plurality of detector elements 1504a-1504c.

[0282] The collection optics subassembly 1502 is configured to collect a return beam 1516 from the sample being measured through a collection site 1510 of the sampling interface (e.g., when a transmitting architecture of an optical measurement system such as those described herein transmits light into the sample being measured), and is configured to direct the return beam 1516 to a condenser lens 1512. The return beam 1516 is projected to emerge from a projected return beam 1518, which has a first dimension (e.g., along the first dimension) upon entering the collection site 1510. Figure 15A The diverging portion of the XZ plane shown in FIG5 and the converging portion of the XZ plane shown in FIG5 at the transition region 1520 are converted from the converging portion of the XZ plane shown in FIG5 to the diverging portion of the XZ plane shown in FIG5 . Figure 15A The return beam 1516 and its corresponding projected return beam 1518 may have the same characteristics as described above. Figure 5A and Figure 5B Any characteristics described for the return beam 504 and the projected return beam 506.

[0283] The collection optics subassembly 1502 also includes a set of lenses (e.g., including an imaging lens 1506 and a relay lens 1508) configured to image the light beam 1518 back onto the condenser lens 1512. For example, the collection optics subassembly 1502 can be configured such that the condenser lens 1512 is positioned at the focal plane of the set of lenses. Additionally, the collection optics subassembly 1502 can be configured such that a transition region 1520 of the projected light return beam 1518 is positioned at the image plane of the set of lenses when the collection optics subassembly 1502 collects the return light beam 1516 from the target sample. In these cases, the angle at which the light rays are incident on the condenser lens 1512 corresponds to the angle at which the light rays enter the sampling interface 1510.

[0284] The condenser lens 1512 is configured to generate a plurality of measurement beams 1524a-1524c from the return beam 1518, each of which is measured by a corresponding detector in the plurality of detector elements 1504a-1504c. Each of the measurement beams 1524a-1524c includes light entering the collection site 1510 at a different corresponding angular range. For example, Figure 15A Depicted are a first light beam 1522a representing light in the return light beam 1516 that enters the collection site 1510 at a first angle, a second light beam 1522b representing light in the return light beam 1516 that enters the collection site 1510 at a second angle different from the first angle, and a third light beam 1522c representing light in the return light beam 1516 that enters the collection site 1510 at a third angle different from the first and second angles.

[0285] The position at which each light ray impinges upon the plurality of detector elements 1504a-1504c depends on the angle at which the light ray impinges upon the condenser lens 1512. For example, the light rays of first light ray bundle 1522a, after passing through imaging lens 1506 and relay lens 1508, impinge upon condenser lens 1512 at a first common angle and form a portion of first measurement beam 1524a measured by first detector element 1504a. Similarly, the light rays of second light ray bundle 1522b, after passing through imaging lens 1506 and relay lens 1508, impinge upon condenser lens 1512 at a second common angle and form a portion of second measurement beam 1524b measured by second detector element 1504b. The light rays of third light ray bundle 1522c, after passing through imaging lens 1506 and relay lens 1508, impinge upon condenser lens 1512 at a third common angle and form a portion of third measurement beam 1524c measured by third detector element 1504c.

[0286] Because the return beam 1516 is imaged onto the condenser lens 1512, each ray measured by the multiple detector elements is projected to have passed through the transition region 1520. The collection architecture 1500 can be configured such that, for a target sample, the transition region 1520 is positioned at a sample region that is angle-independent for each of the multiple detector elements 1504a-1504c. In such cases, because the multiple detector elements 1504a-1504c each measure light projected to pass through the same transition region 1520, the detector elements 1504a-1504c will measure light having approximately the same path length distribution. Additionally, because the multiple detector elements 1504a-1504c each measure light projected to pass through the transition region 1520 at a different range of angles, the multiple detector elements 1504a-1504c will measure light having different sampling depth distributions.

[0287] For example, Figure 15B An example diagram 1530 is shown, which shows that when the collection architecture 1500 is incorporated as Figure 9A Graph 1530 illustrates the range of path lengths and sampling depths of light collected by each measurement channel of collection architecture 1500 for collection architecture 904 of optical measurement system 900. Specifically, graph 1530 includes a first distribution 1532a representing the range of possible path length and sampling depth combinations (with a minimum threshold probability) for light measured by first detector element 1504a; a second distribution 1532b representing the range of possible path length and sampling depth combinations (with a minimum threshold probability) for light measured by second detector element 1504b; and a third distribution 1532c representing the range of possible path length and sampling depth combinations (with a minimum threshold probability) for light measured by third detector element 1504c. As shown, first, second, and third distributions 1532a-1532c have approximately the same path length distribution, but first detector element 1504a measures light that, on average, has a deeper sampling depth than light measured by second detector element 1504b. Similarly, second detector element 1504b measures light having, on average, a deeper sampling depth than light measured by third detector element 1504c.These distributions can improve the accuracy of measurements performed by the optical measurement systems described herein.

[0288] In some variations, the condenser lens 1512 may be configured as an immersion condenser lens. In these variations, the condenser lens 1512 may be formed from a surface of a substrate 1514. The plurality of detector elements 1504a-1504c may also be formed on the substrate 1514 (e.g., using one or more epitaxial layers grown on the substrate 1514). Examples of detectors with immersion lenses are described in more detail in U.S. Patent Publication No. US2022 / 0037543A1, entitled "Wideband Back-Illuminated Electromagnetic Radiation Detectors," the entire contents of which are incorporated herein by reference. Additionally, in some variations, the substrate 1514 may further include an aperture layer 1526 formed of a light-blocking material and at least partially surrounding the condenser lens 1512. The aperture layer 1526 may define an aperture of the condenser lens 1512.

[0289] In some variations, the collection optics subassembly may include multiple immersion lenses, each associated with a different plurality of detector elements. In these cases, each plurality of detector elements may measure light having a common path length distribution and a different sampling depth distribution, while different plurality of detector elements may measure light having a different path length distribution. Figure 16A and Figure 16B One such variation of a collection architecture 1600 as described herein is depicted. The collection architecture 1600 includes a collection optics subassembly 1602 having a plurality of condenser lenses 1612a-1612c. The collection architecture 1600 also includes a plurality of groups of detector elements, each group of detector elements being positioned to receive light from a different one of the plurality of condenser lenses 1612a-1612c.

[0290] exist Figure 16A and Figure 16B In the example shown, the collection architecture 1600 includes three condenser lenses 1612a-1612c and three pluralities of detector elements. Specifically, a first plurality of detector elements 1604a-1604c is positioned to measure light passing through the first condenser lens 1612a, a second plurality of detector elements 1644a-1644c is positioned to measure light passing through the second condenser lens 1612b, and a third plurality of detector elements 1684a-1684c is positioned to measure light passing through the third condenser lens 1612c. Each of the plurality of detector elements 1604a-1604c, 1644a-1644c, and 1684a-1684c is positioned to measure light passing through the third condenser lens 1612c. Figure 16A and Figure 16B 1 is shown as having three detector elements, but it should be understood that in some cases one or more of the plurality of detector elements may have two or four or more detector elements.

[0291] The collection optical subassembly 1602 is configured to collect a plurality of return beams from the sample being measured (e.g., when a transmitting architecture of an optical measurement system such as those described herein transmits light into the sample being measured) through a collection site 1610 of the sampling interface. Specifically, the plurality of return beams includes a first return beam 1616 (at Figure 16A ), a second return beam (not shown), and a third return beam 1656. When the light enters the collection point 1610 of the sampling interface, the multiple return beams can at least partially overlap. The collection optics subassembly 1602 is further configured to direct the first return beam 1616 to a first condenser lens 1612a, the second return beam to a second condenser lens 1612b, and the third return beam to a third condenser lens 1612c.

[0292] Each of the plurality of return beams is projected to emanate from a corresponding projected return beam. For example, a first return beam 1616 is projected to emanate from a first projected return beam 1618a, a second return beam is projected to emanate from a second projected return beam 1618b, and a third return beam 1656 is projected to emanate from a third projected return beam 1618c. Each of the plurality of projected return beams 1618a-1618c may include a beam that is projected along a first dimension (e.g., along a first dimension) as it enters the collection site 1610. Figure 16A and Figure 16B In addition, these diverging portions diverge from the corresponding converging portions (in the XZ plane shown in FIG. 16 ) at a plurality of transition regions 1620a-1620c. Figure 16A and Figure 16B Each return beam and its corresponding projected return beam may have the same characteristics as those described above. Figure 5A and Figure 5B Any characteristics described for the return beam 504 and the projected return beam 506.

[0293] The collection optics subassembly 1602 also includes a set of lenses (e.g., including an imaging lens 1606 and a relay lens 1608 separated by an aperture 1628) configured to image the plurality of return beams onto a plurality of condenser lenses 1612a-1612c. For example, the collection optics subassembly 1602 can be configured such that each of the plurality of condenser lenses 1612a-1612c is positioned at a focal plane of the set of lenses. Additionally, the collection optics subassembly 1602 can be configured such that each of the plurality of transition regions 1620a-1620c of the projected light return beams 1618a-1618c is positioned at an image plane of the set of lenses when the collection optics subassembly 1602 collects the plurality of return beams from the target sample. In these cases, the selection of which condenser lens receives a given ray depends on which transition region 1620a-1620c the ray is projected to intersect. Additionally, the angle at which light is incident on a given condenser lens corresponds to the angle at which the light enters the sampling interface via the collection site 1610 .

[0294] As described in more detail below, each of the condenser lenses 1612a-1612c is configured to generate a plurality of measurement beams from its corresponding return beam that are measured by a plurality of detector elements associated with the condenser lens. Each of the plurality of measurement beams corresponds to a different angular range selected from the return beam. For example, Figure 16A As shown, a first detector element 1604a of the first plurality of detector elements 1604a-1604c measures a first ray bundle 1622a of the first return light beam 1616, which includes light rays that are projected to intersect the first transition region 1620a and enter the collection site 1610 at a first range of angles. A second detector element 1604b of the first plurality of detector elements 1604a-1604c measures a second ray bundle 1622b of the first return light beam 1616, which includes light rays that are projected to intersect the first transition region 1620a and enter the collection site 1610 at a second range of angles (different from the first range of angles). A third detector element 1604c of the first plurality of detector elements 1604a-1604c measures a third ray bundle 1622c of the first return light beam 1616, which includes light rays that are projected to intersect the first transition region 1620a and enter the collection site 1610 at a third range of angles (different from the first and second ranges of angles).

[0295] Similarly, if Figure 16BAs shown, a first detector element 1684a of the third plurality of detector elements 1684a-1684c measures a first ray bundle 1662a of the third return light beam 1656, which includes light rays that are projected to intersect the third transition region 1620c and enter the collection site 1610 at a first range of angles. A second detector element 1684b of the third plurality of detector elements 1684a-1684c measures a second ray bundle 1662b of the third return light beam 1656, which includes light rays that are projected to intersect the third transition region 1620c and enter the collection site 1610 at a second range of angles. A third detector element 1684c of the third plurality of detector elements 1684a-1684c measures a third ray bundle 1662c of the third return light beam 1656, which includes light rays that are projected to intersect the third transition region 1620c and enter the collection site 1610 at a third range of angles.

[0296] In this way, each plurality of detector elements can measure light having a common path length distribution and a different sampling depth distribution, such as described herein with respect to Figure 15A The collection architecture 1500 is described above. The collection architecture 1600 can be configured such that each of the plurality of transition regions 1620a-1620c is positioned at a corresponding sample region for a target sample, the corresponding sample region being angularly independent for a corresponding plurality of detector elements. Specifically, the first transition region 1620a can be angularly independent for each of the first plurality of detector elements 1604a-1604c, the second transition region 1620b can be angularly independent for each of the second plurality of detector elements 1644a-1644c, and the third transition region 1620c can be angularly independent for each of the third plurality of detector elements 1684a-1684c. In these cases, the path length distribution can be substantially the same within a given plurality of detector elements, but can vary between different pluralities of detector elements.

[0297] Figure 16C An example diagram 1630 is shown, which shows that when the collection architecture 1600 is incorporated as Figure 9B 16. The collection architecture 934 of the optical measurement system 930 depicts a range of path lengths and sampling depths for light collected by each measurement channel of the collection architecture 1600. Specifically, the graph 1630 includes a first set of distributions 1632a-1632c, which represent a range of possible path length and sampling depth combinations (with a minimum threshold probability) for light measured by the first plurality of detector elements 1604a-1604c, respectively. The graph 1630 also includes a second set of distributions 1634a-1634c corresponding to the second plurality of detector elements 1644a-1644c and a third set of distributions 1636a-1636c corresponding to the third plurality of detector elements 1684a-1684c.

[0298] As shown, the first plurality of detector elements 1604a-1604c can measure light having a common path length distribution but different sampling depth distributions. Similarly, the second plurality of detector elements 1644a-1644c can measure light having a common path length distribution but different sampling depth distributions. That is, the second plurality of detector elements 1644a-1644c can measure light having, on average, a longer optical path length than the light measured by the first plurality of detector elements 1604a-1604c. In summary, the various detector elements can selectively measure different combinations of optical path lengths and sampling depths. Additionally, the relative positions of the apertures 1628 can be adjusted to change the relative sampling depth differences between different pluralities of detector elements, such as described herein with respect to 14A to 14F described.

[0299] and Figure 15A As with the condenser lens 1512 of FIG. 1 , a plurality of condenser lenses 1612a-1612c can be formed as part of a common substrate 1614 to form a plurality of immersion condenser lenses. In these variations, the first, second, and third pluralities of detector elements 1604a-1604c, 1644a-1644c, 1684a-16840c can be formed on the substrate 1614. Additionally, the substrate 1614 can further include an aperture layer 1626, such as described in greater detail herein.

[0300] In other variations of the collection architectures described herein, the collection optics subassembly can be configured such that multiple detector elements associated with a condenser lens measure light having a common sampling depth distribution but different path length distributions. Figure 17A One such variation of a collection architecture 1700 as described herein is depicted. The collection architecture 1700 includes a collection optics subassembly 1702 having a plurality of condenser lenses 1712a-1712c (which may be a plurality of immersion condenser lenses formed on a common substrate, as discussed in greater detail herein). The collection architecture 1700 also includes a plurality of groups of detector elements, each group of detector elements being positioned to receive light from a different one of the plurality of condenser lenses 1712a-1712c.

[0301] exist Figure 17AIn the example shown, the collection architecture 1700 includes three condenser lenses 1712a-1712c and three pluralities of detector elements. Specifically, a first plurality of detector elements 1704a-1704c is positioned to measure light passing through the first condenser lens 1712a, a second plurality of detector elements 1744a-1744c is positioned to measure light passing through the second condenser lens 1712b, and a third plurality of detector elements 1784a-1784c is positioned to measure light passing through the third condenser lens 1712c. Each of the plurality of detector elements 1704a-1704c, 1744a-1744c, and 1784a-1784c is positioned to measure light passing through the third condenser lens 1712c. Figure 17A 1 is shown as having three detector elements, but it should be understood that in some cases one or more of the plurality of detector elements may have two or four or more detector elements.

[0302] The collection optical subassembly 1702 is configured to collect a plurality of return beams from the sample being measured (e.g., when a transmitting architecture of an optical measurement system such as those described herein transmits light into the sample being measured) through a collection site 1710 of the sampling interface. Specifically, the plurality of return beams include a first return beam 1716, a second return beam (at Figure 17A A portion thereof is shown, specifically the light beam 1742) and the third return beam (in Figure 17A 17. A portion of the light beams, specifically light beam bundle 1782, is shown in FIG. 17. When the light enters the collection point 1710 of the sampling interface, the multiple return light beams may at least partially overlap. The collection optics subassembly 1702 is further configured to direct a portion of each of the multiple return light beams to each of the plurality of condenser lenses 1712a-1712c.

[0303] Each of the plurality of return beams is projected to emanate from a corresponding projected return beam. For example, a first return beam 1716 is projected to emanate from a first projected return beam 1718a, a second return beam is projected to emanate from a second projected return beam 1718b, and a third return beam is projected to emanate from a third projected return beam 1718c. Each of the plurality of projected return beams 1718a-1718c may include a diverging portion that diverges along a first dimension (e.g., along a first dimension) as it enters the collection site 1710. Figure 17A In addition, these diverging portions diverge from the corresponding converging portions (in the XZ plane shown in FIG. 17 ) at a plurality of transition regions 1720a-1720c. Figure 17A Each return beam and its corresponding projected return beam may have the same characteristics as those described above. Figure 5A and Figure 5B Any characteristics described for the return beam 504 and the projected return beam 506.

[0304] The collection optics subassembly 1702 also includes a set of lenses (e.g., including lens 1706) configured to direct a portion of each of the plurality of return beams to each of the plurality of condenser lenses 1712a-1712c. For example, the collection optics subassembly 1702 can be configured to collimate each return beam and direct the collimated return beam toward the plurality of condenser lenses 1712a-1712c. Specifically, each collimated return beam can be incident on the plurality of condenser lenses at a different angle. Thus, each of the plurality of condenser lenses 1712a-1712c receives a collimated portion of each of the plurality of return beams, wherein the collimated portions enter the condenser lens at a different angle. Each condenser lens will direct each collimated portion to a different detector element.

[0305] For example, first return beam 1716 includes first light beam 1722a that enters collection site 1710 at a first angular range, second light beam 1722b that enters collection site 1710 at a second angular range different from the first angular range, and third light beam 1722c that enters collection site 1710 at a third angular range different from the first and second angular ranges. First light beam 1722a can be directed to first condenser lens 1712a, which directs first light beam 1722a (e.g., as first measuring beam 1724a) to first detector element 1704a of the first plurality of detector elements 1704a-1704c. Second light beam 1722b can be directed to second condenser lens 1712b, which directs second light beam 1722b (e.g., as second measuring beam 1724b) to first detector element 1744a of the second plurality of detector elements 1744a-1744c. The third light beam 1722c can be directed to a third condenser lens 1712c, which directs the third light beam 1722c (e.g., as a third measuring beam 1724c) to a first detector element 1784a in a third plurality of detector elements 1784a-1784c. Thus, a first detector element from each of the first, second, and third pluralities of detector elements 1704a-1704c, 1744a-1744c, 1784a-1784c measures light from the first return beam 1716. Similarly, a second detector element from each of the first, second, and third pluralities of detector elements 1704a-1704c, 1744a-1744c, 1784a-1784c measures light from the second return beam. A third detector element from each of the first, second, and third pluralities of detector elements 1704a-1704c, 1744a-1744c, 1784a-1784c measures light from the third return light beam.

[0306] As a result, each of the plurality of detector elements measures light from a different return beam, but having the same angular content. For example, third condenser lens 1712c receives third ray bundle 1722c (e.g., entering collection site 1710 at a third angular range), ray bundle 1742 from the second return beam that enters collection site 1710 at a third angular range, and ray bundle 1782 from the third return beam that enters collection site 1710 at a third angular range. Thus, third plurality of detector elements 1784a-1784c may include first detector element 1784a that receives third ray bundle 1724c (e.g., as third measurement beam 1724c), second detector element 1784b that receives ray bundle 1742 (e.g., as fourth measurement beam 1724d), and third detector element 1784c that receives ray bundle 1782 (e.g., as fifth measurement beam 1724e).

[0307] The collection optics subassembly 1702 can be configured such that, when the collection optics subassembly 1702 collects a plurality of return beams from a target sample, each of the plurality of transition regions 1720a-1720c can be positioned at a corresponding sample region that is angularly independent for detector elements from each of the first, second, and third pluralities of detector elements 1704a-1704c, 1744a-1744c, 1784a-1784c. For example, the first transition region 1720a can be angularly independent for a first detector element of each of the plurality of detector elements (e.g., the first detector element 1704a of the first plurality of detector elements 1704a-1704c, the first detector element 1744a of the second plurality of detector elements 1744a-1744c, and the first detector element 1784a of the third plurality of detector elements 1784a-1784c). Additionally, because these detector elements all measure light projected from the same transition region 1720a, they can measure light having approximately the same path length distribution but different sampling depth distributions.

[0308] Similarly, the second transition region 1720b may be angularly independent for a second detector element of each of the plurality of detector elements (e.g., second detector element 1704b of the first plurality of detector elements 1704a-1704c, second detector element 1744b of the second plurality of detector elements 1744a-1744c, and third detector element 1784c of the third plurality of detector elements 1784a-1784c). The third transition region 1720c may be angularly independent for a third detector element of each of the plurality of detector elements (e.g., third detector element 1704c of the first plurality of detector elements 1704a-1704c, third detector element 1744c of the second plurality of detector elements 1744a-1744c, and third detector element 1784c of the third plurality of detector elements 1784a-1784c).

[0309] In general, the first, second and third pluralities of detector elements 1704a-1704c, 1744a-1744c, 1784a-1784c can collectively measure light having the same set of path length distributions and sampling depth distributions as the light collected by the first, second and third pluralities of detector elements 1604a-1604c, 1644a-1644c and 1684a-1684c described herein with respect to the collection architecture 1600. Figure 17B An example diagram 1730 is shown, which shows that when the collection architecture 1700 is incorporated as Figure 9B 934 of the optical measurement system 930, and the range of path lengths and sampling depths of light collected by each measurement channel of the collection architecture 1700. Specifically, the graph 1730 includes a first set of distributions 1732a-1732c, which respectively represent the range of possible path length and sampling depth combinations (with minimum threshold probability) of light measured by the first plurality of detector elements 1704a-1704c. The graph 1730 also includes a second set of distributions 1734a-1734c corresponding to the second plurality of detector elements 1744a-1744c and a third set of distributions 1736a-1736c corresponding to the third plurality of detector elements 1784a-1784c.

[0310] As shown, first, second, and third detector elements 1704a, 1704b, 1704c of a first plurality of detector elements 1704a-1704c can measure light having a first path length distribution, a second path length distribution, and a third path length distribution, respectively. First, second, and third detector elements 1744a, 1744b, 1744c of a second plurality of detector elements 1744a-1744c can also measure light having a first path length distribution, a second path length distribution, and a third path length distribution, respectively. The second plurality of detector elements 1744a-1744c measure light having, on average, a deeper sampling depth than the light measured by the first plurality of detector elements 1704a-1704c. Similarly, first, second, and third detector elements 1784a, 1784b, 1784c of a third plurality of detector elements 1784a-1784c can also measure light having a first path length distribution, a second path length distribution, and a third path length distribution, respectively. The third plurality of detector elements 1784a-1784c measures light having, on average, a deeper sampling depth than the light measured by the second plurality of detector elements 1744a-1744c.

[0311] In some cases, it may be desirable for the collection architecture to collect and measure multiple copies of a given return beam from the same emission beam. Each of these copies can be aligned along the second dimension of the collection architecture and can collectively approximate a single return beam with a higher aspect ratio. 18A to 18C This principle is shown in , which can be applied to any variant of the optical measurement system described herein. 18A to 18C Depicts top views of different variations of focusing architectures utilizing focusing lenses, such as those described above with respect to Figures 15A to 17B The concentrating architecture is described.

[0312] For example, Figure 18A One such variation of a photonic integrated circuit 1800 is shown. As shown, the collection architecture 1800 includes two optical collection subassemblies on opposite sides of a transmit architecture (not shown). The transmit architecture is configured to transmit a transmit beam from an optical measurement system (schematically represented by rectangle 1801). As shown, the transmit beam 1801 is transmitted in a second dimension (e.g., along Figure 18A The Y-axis shown) is greater than the first dimension (e.g., along Figure 18B The X-axis shown is longer, such as about Figure 3A and 3B18. The emission beam 1801 is emitted into the sample being measured (e.g., through an emission point of the sampling interface), and the collection architecture 1800 collects a portion of the light from the emission beam 1801 that returns to the optical measurement system. Specifically, a first collection optical subassembly 1803a collects light returning from a first side of the transmission architecture (e.g., light entering the optical measurement system via a first collection site of the sampling interface), and a second collection optical subassembly 1803b collects light returning from a second side of the transmission architecture opposite the first side (e.g., light entering the optical measurement system via a second collection site of the sampling interface).

[0313] As shown, the first collection optics subassembly 1803a includes at least one condenser lens (e.g., a first plurality of condenser lenses 1804a-1804c), each condenser lens positioned to direct light to a different corresponding plurality of detector elements. The first collection optics subassembly 1803a may also include additional lenses or other components configured to direct light from the sampling interface to the at least one condenser lens (e.g., such as those described herein). Figures 15A to 17B The collection architecture is described in more detail in Figure 18A In the variation shown, a first condenser lens 1804a is positioned to direct light to each of a first plurality of detector elements 1802a, a second condenser lens 1804b is positioned to direct light to each of a second plurality of detector elements 1802b, and a third condenser lens 1804c is positioned to direct light to each of a third plurality of detector elements 1802c.

[0314] Similarly, the second collection optics subassembly 1803b includes at least one condenser lens (e.g., a second plurality of condenser lenses 1804d-1804f), each condenser lens positioned to direct light to a different corresponding plurality of detector elements. The second collection optics subassembly 1803b may also include additional lenses or other components configured to direct light from the sampling interface to the at least one condenser lens (e.g., such as described herein with respect to Figures 15A to 17B The collection architecture is described in more detail in Figure 18A In the variation shown, a fourth condenser lens 1804d is positioned to direct light to each of a fourth plurality of detector elements 1802d, a fifth condenser lens 1804e is positioned to direct light to each of a fifth plurality of detector elements 1802e, and a sixth condenser lens 1804f is positioned to direct light to each of a sixth plurality of detector elements 1802f.

[0315] In some variations, the collection architecture 1800 is configured symmetrically around the transmission architecture such that each detector element associated with the first collection optics subassembly 1803a measures light having approximately the same path length and sampling depth distribution as the corresponding detector element associated with the first collection optics subassembly 1803a. This can allow the output signals to be combined without changing the path length and sampling depth distribution associated with the output signals. For example, first detector element 1806a of the third plurality of detector elements 1802c can measure light having approximately the same path length and sampling depth distribution as light measured by first detector element 1808a of the sixth plurality of detector elements 1802f. The output signals of these measurement channels can be combined to form a first combined output signal. Similarly, second detector element 1806b of the third plurality of detector elements 1802c can measure light having approximately the same path length and sampling depth distribution as light measured by second detector element 1808b of the sixth plurality of detector elements 1802f. The output signals of these measurement channels can be combined to form a second combined output signal. Additionally, third detector elements 1806c, 1808c of the third and sixth pluralities of detector elements 1802c, 1802f may measure light having a path length distribution and a sampling depth distribution.The output signals of these measurement channels may be combined to form a third combined output signal.

[0316] exist Figure 18A In the illustrated variation, each of the plurality of detector elements 1802a-1802f is configured as a one-dimensional array of detector elements. Thus, to improve the collection efficiency of the optical measurement system, the length of each detector element along the second dimension depends on the length of the emission beam 1801 along the second dimension. A longer emission beam 1801, and thus a longer corresponding detector element, can increase the amount of light measured by a given detector element while still maintaining the path length and sampling depth profile associated with that detector element. However, in practice, it can be difficult (e.g., from a manufacturing or yield perspective) to produce detector elements with such lengths or aspect ratios.

[0317] Therefore, in some variations, it may be necessary to replace the detector elements with multiple shorter ones. Figure 18A Each detector element of the collection architecture. Figure 18B One such variation of the collection architecture 1810 is shown. Figure 18AThe collection architecture 1800 is the same, except that the plurality of detector elements 1802a-1802f is replaced by a different plurality of detector elements 1812a-1812f, each of which is configured as a two-dimensional array of detector elements. In these cases, the light measured by the respective detector elements can have approximately the same sampling depth and path length distribution within a column (e.g., along the second dimension) and can have different sampling depth and / or path length distributions between rows (e.g., along the second dimension).

[0318] For example, a third plurality of detector elements 1812c is positioned to receive light from a third condenser lens 1804c. The third plurality of detector elements 1812c includes a first group of detector elements 1814a-1814c, a second group of detector elements 1816a-1816c, and a third group of detector elements 1818a-1818c. The first detector element from each of these groups (e.g., detector elements 1814a, 1816a, and 1818a) can measure light having approximately the same path length distribution and sampling depth distribution, and the output signals from these measurement channels can be combined as described herein. In this way, these detector elements are approximately the same as those composed of Figure 18A , except that the individual detector elements may have a smaller length along the second dimension (and therefore a smaller aspect ratio). Similarly, the output signals of detector elements 1814b, 1816b, and 1818b may be combined to approximate the light received by Figure 18A The light is measured by detector element 1806b.

[0319] In other variations, one or more components of the collection optics subassembly may be replicated along a second dimension. Figure 18C One such variation of the collection architecture 1820 is shown. Figure 18B The collection architecture 1800 is identical to that of FIG. 1 , except that the first collection optical subassembly 1813a and the second collection optical subassembly 1813b are replaced by different first collection optical subassemblies 1823a and second collection optical subassemblies 1823b. Specifically, each of the plurality of condenser lenses 1804a-1804f is replaced by a one-dimensional array of condenser lenses 1834a-1834f. For example, instead of Figure 18BThe first collection optics subassembly 1833a includes a third condenser lens 1804c, and the first collection optics subassembly 1833a includes a third one-dimensional condenser lens array 1834c. Specifically, the one-dimensional array of condenser lenses 1834c includes a first condenser lens 1836a positioned above a first group of detector elements 1814a-1814c of the first plurality of detector elements 1812c, a second condenser lens 1836b positioned above a second group of detector elements 1816a-1816c of the first plurality of detector elements 1812c, and a third condenser lens 1836c positioned above a third group of detector elements 1818a-1818c of the first plurality of detector elements 1812c.

[0320] Thus, each of the first and second collection optics subassemblies 1833a and 1833b can include a two-dimensional array of condenser lenses. In variations where one of these collection optics subassemblies includes additional lenses or components positioned above the condenser lenses, these components may or may not be replicated along the second dimension. Figure 16A and Figure 16B Taking the imaging lens 1606 of the collection architecture 1600 as an example, in some variations, the first collection optics subassembly 1833a may include a single imaging lens positioned above all of the condenser lenses and performing the functions of imaging lens 1606 for each condenser lens. In other variations, multiple imaging lenses may be positioned along a second dimension, with each of these lenses performing the functions of imaging lens 1606 for a different subset of the condenser lenses. For example, a first imaging lens may direct light to a first condenser lens (e.g., condenser lens 1836a) in each of the one-dimensional array of condenser lenses 1834a-1834c, a second imaging lens may direct light to a second condenser lens (e.g., condenser lens 1836b) in each of the one-dimensional array of condenser lenses 1834a-1834c, and so on. Thus, there is flexibility in the design of the optical measurement systems described herein to increase the effective aspect ratio of light emitted into and measured from the measured sample.

[0321] Optical measurement system with mobile diffuser

[0322] In various embodiments of the optical measurement systems described herein, the optical measurement system can include a diffuser as part of its transmission architecture. In some of these variations, the optical measurement system can be configured to move the diffuser within the optical measurement system while performing spectral measurements. Specifically, moving the diffuser within a single measurement or between consecutive measurements can be used to reduce noise associated with measurements performed by the optical measurement system. When the light source of the light source unit described herein includes a coherent light source (such as a laser), measurements performed using coherent illumination can be subject to coherent noise (also referred to herein as "speckle" noise).

[0323] Specifically, interference of coherent light as it scatters through a sample can result in spatial intensity variations in the light received by the detector elements. These spatial variations can reduce the signal-to-noise ratio of the light measured by the various measurement channels of the optical measurement systems described herein. When a diffuser is configured to receive an input light beam (e.g., Figure 11A and Figure 11B The input beam 1105 or Figure 12 1240) and generates a diverging output beam therefrom (e.g., Figure 11A and Figure 11B The output beam 1110 or Figure 12 When the diffuser is positioned relative to the input beam (e.g., output beam 1220), movement of the diffuser relative to the input beam can cause the input beam to be incident on different portions of the diffuser. This can change the distribution of phase changes applied to the input beam as it passes through the diffuser and generates the output beam. The optical measurement system can be used to perform otherwise identical measurements, but measurements taken with the diffuser at different diffuser positions may have different speckle noise states (e.g., different spatial intensity variations). Therefore, multiple measurements taken with the diffuser at different positions can be analyzed or otherwise combined to average out some of the speckle noise. This can therefore increase the signal-to-noise ratio (SNR) of the spectral measurements performed by the optical measurement system.

[0324] Therefore, any optical measurement system described herein that includes a diffuser may also incorporate an electromagnetic actuator arrangement configured to move the diffuser relative to a fixed base. It should be understood that, when used in the context of an electromagnetic actuator arrangement, the term "fixed" is intended as a relative term to indicate the positioning of a particular component fixed within the electromagnetic actuator arrangement. Specifically, an electromagnetic actuator arrangement may include one or more "movable" components that can move relative to other "fixed" components of the electromagnetic actuator arrangement. When such an electromagnetic actuator arrangement is incorporated into an optical measurement system (or a device incorpora...

Claims

1. An optical measurement system, comprising: a sampling interface defining a transmission site and a set of collection sites, each of the collection sites being laterally spaced from the transmission site; a transmission architecture configured to transmit a transmission light beam that exits the sampling interface through the transmission site; and a collection architecture comprising a set of detector elements positioned to measure light that has entered the sampling interface through the set of collection sites, wherein: When the transmitting structure transmits the transmitting light beam, the set of detector elements forms a set of measurement channels; The emission light beam converges in a first dimension as it leaves the sampling interface; and In case that the emission light beam is emitted into a target sample, the emission light beam projects into a transition region in the target sample that is angle-independent with respect to at least one measurement channel of the set of measurement channels.

2. The optical measurement system according to claim 1, wherein: The transmit architecture is configured such that when the transmit light beam leaves the sampling interface, the transmit light beam has a beam divergence half-angle of at least 15 degrees in the first dimension.

3. The optical measurement system according to claim 2, wherein: The transmit architecture is configured such that when the transmit light beam exits the sampling interface, the transmit light beam has a beam divergence half-angle of at least 30 degrees in the first dimension.

4. The optical measurement system according to any one of claims 1 to 3, wherein: The set of collection sites includes a first collection site and a second collection site; The sending site is positioned between the first collecting site and the second collecting site; and The set of detector elements comprises: a first set of detector elements positioned to measure light that has entered the sampling interface through the first collection site; and A second set of detector elements is positioned to measure light that has entered the sampling interface through the second collection site.

5. The optical measurement system according to claim 4, wherein: When the transmitting architecture transmits the transmitting light beam, the first group of detector elements forms a first group of measurement channels; When the transmitting architecture transmits the transmit light beam, the second set of detector elements forms a second set of measurement channels; and The transition region in the target sample is independent of the angles of the first set of measurement channels and the second set of measurement channels.

6. The optical measurement system according to claim 5, wherein: The transmit architecture is configured such that when the transmit beam leaves the sampling interface, the transmit beam has a first beam width in the first dimension and a second beam width in a second dimension perpendicular to the first dimension; and The second beamwidth is at least eight times greater than the first beamwidth.

7. An optical measurement system comprising: a sampling interface defining a transmission site and a first collection site laterally spaced from the transmission site; a transmission architecture configured to transmit a transmission light beam that exits the sampling interface through the transmission site; and A collection architecture comprising a first detector element and configured to: collecting a first returning light beam entering the sampling interface through the first collecting site; as well as directing the return beam to the first detector element, wherein: When the transmitting structure transmits the transmitting light beam, the first detector element forms a first measuring channel; The first return beam diverges in a first dimension when it enters the sampling interface; and In case the first return beam is collected from a target sample, the first return beam is projected from a first transition region in the target sample that is angularly independent of the first measurement channel.

8. The optical measurement system according to claim 7, wherein: The collection architecture is configured such that the first return beam has a beam divergence half-angle of at least 15 degrees in the first dimension when the return beam enters the sampling interface.

9. The optical measurement system according to claim 8, wherein: The collection architecture is configured such that the first return beam has a beam divergence half-angle of at least 30 degrees in the first dimension when the return beam enters the sampling interface.

10. The optical measurement system according to any one of claims 7 to 9, wherein: The collection architecture includes a second detector element and is configured to: collecting a second returning light beam that enters the sampling interface through the first collecting site; as well as directing the second return beam to the second detector element, wherein: When the transmitting structure transmits the transmitting light beam, the second detector element forms a second measuring channel; and The second return beam diverges in the first dimension when it enters the sampling interface.

11. The optical measurement system according to claim 10, wherein: In case the second return beam is collected from the target sample, the second return beam is projected from a second transition region in the target sample that is angularly independent of the second measurement channel.

12. The optical measurement system according to any one of claims 7 to 9, wherein: the sampling interface defines a second collection site, the second collection site being positioned such that the transmission site is positioned between the first collection site and the second collection site; The collection architecture includes a second detector element and is configured to: collecting a second returning light beam entering the sampling interface through the second collecting site; as well as directing the second return beam to the second detector element; When the transmitting structure transmits the transmitting light beam, the second detector element forms a second measuring channel; The second return beam diverges in the first dimension when it enters the sampling interface; and In case the second return beam is collected from the target sample, the second return beam is projected from a second transition region in the target sample that is angularly independent of the second measurement channel.

13. The optical measurement system according to any one of claims 7 to 9, wherein: The collection architecture is configured such that when the first return beam enters the sampling interface, the first return beam has a first beam width in the first dimension and a second beam width in a second dimension perpendicular to the first dimension; and The second beamwidth is at least eight times greater than the first beamwidth.

14. An optical measurement system comprising: a sampling interface defining a transmission site and a first collection site laterally spaced from the transmission site; a transmission architecture configured to transmit a transmission light beam that exits the sampling interface through the transmission site; and A collection architecture comprising a first detector element and configured to: collecting a first returning light beam that passes through the collection site and enters the first sampling interface; as well as directing the return beam to the first detector element, wherein: When the transmitting structure transmits the transmitting light beam, the first detector element forms a measuring channel; The emitted light beam converges in a first dimension as it leaves the sampling interface; The return beam diverges in the first dimension when it enters the sampling interface; and The optical measurement system is configured such that, when the optical measurement system is used to measure a characteristic of a target sample: The emission light beam is projected into a first transition region in the target sample that is independent of the measurement channel angle; and The return beam is projected from a second transition region in the target sample that is independent of the measurement channel angle.

15. The optical measurement system of claim 14, wherein: The transmit architecture is configured such that when the transmit light beam leaves the sampling interface, the transmit light beam has a beam divergence half-angle of at least 15 degrees in the first dimension.

16. An optical measurement system according to claim 14 or claim 15, wherein: The collection architecture is configured such that the first return beam has a beam divergence half-angle of at least 15 degrees in the first dimension when the return beam enters the sampling interface.

17. An optical measurement system according to claim 14 or 15, wherein: The collection architecture includes a second detector element and is configured to: collecting a second returning light beam that enters the sampling interface through the first collecting site; as well as directing the second return beam to the second detector element, wherein: When the transmitting structure transmits the transmitting light beam, the second detector element forms a second measuring channel; and The second return beam diverges in the first dimension when it enters the sampling interface.

18. The optical measurement system of claim 17, wherein: The first transition region is independent of the second measurement channel angle.

19. The optical measurement system of claim 17, wherein: In the case where the second return beam is collected from the target sample, the second return beam is projected from a third transition region in the target sample that is angularly independent of the second measurement channel.

20. The optical measurement system according to claim 14 or 15, wherein: the sampling interface defines a second collection site, the second collection site being positioned such that the transmission site is positioned between the first collection site and the second collection site; The collection architecture includes a second detector element and is configured to: collecting a second returning light beam entering the sampling interface through the second collecting site; as well as directing the second return beam to the second detector element; When the transmitting structure transmits the transmitting light beam, the second detector element forms a second measuring channel; The second return beam diverges in the first dimension when it enters the sampling interface; and In the case where the second return beam is collected from the target sample, the second return beam is projected from a third transition region in the target sample that is angularly independent of the second measurement channel.

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