Optical system for reference switching

Abstract

The present disclosure relates to an optical system for reference switching, and specifically discloses a system for determining the properties of a sample. The system includes one or more light sources, a detector array, a first substrate, and a second substrate. The first substrate includes illumination optics and a first collection optic. The illumination optics are configured to receive light emitted by the one or more light sources and redirect the light towards the sample. The first collection optic is configured to receive at least a portion of the returned light of the light and redirect the light towards the detector array. The second substrate includes a second collection optic. The second collection optic includes a lens and is configured to receive at least a portion of the returned light of the light and redirect at least a portion of the returned light of the light to the first collection optic. The illumination optics and the first collection optic are formed on one or more surfaces of the first substrate. The detector array is configured to detect the light redirected by the first collection optic and generate one or more signals indicative of the properties of the sample.

Description

[0001] This application is a divisional application of the patent application for invention with the application number 201780024955.2, the application date of April 13, 2017, and the invention title of "Optical System for Reference Switching". Technical Field

[0002] The present invention generally relates to a reference switching architecture capable of detecting one or more substances in a sample, and more specifically, capable of re - imaging one or more optical paths in a sample. Background Art

[0003] Absorption spectroscopy is an analytical technique that can be used to determine one or more properties of a sample. Conventional systems and methods for absorption spectroscopy can include emitting light into the sample. As the light transmits through the sample, a portion of the light energy is absorbed at one or more wavelengths. This absorption can cause a change in the properties of the light leaving the sample. The properties of the light leaving the sample can be compared with the properties of the light leaving a reference object, and one or more properties of the sample can be determined based on this comparison.

[0004] Measurements from one or more detector pixels can be used to determine the properties of the light leaving the sample. Measurements along multiple positions within the sample can be used to accurately determine one or more properties of the sample. These multiple positions can be at different locations within the sample, which can result in optical paths having different path lengths, angles of incidence, and exit positions. However, some conventional systems and methods may not be able to distinguish differences in path length, penetration depth, angle of incidence, exit position, and / or angle of emergence based on measurements along multiple positions within the sample. Those systems and methods that are capable of making measurements at multiple depths or multiple positions may require complex components or detection schemes to correlate the optical paths incident on multiple positions within the sample. These complex components or detection schemes can not only limit the accuracy of re - imaging and resolving multiple optical paths, but also limit the size and / or configuration of the optical system. Therefore, a compact optical system that can accurately re - image and resolve multiple optical paths within a sample may be desirable. Summary of the Invention

[0005] The present invention relates to systems and methods for measuring one or more properties of a sample. The system can include a light source, optics, a reference object, a detector array, and a controller (and / or logic). The disclosed systems and methods are capable of measuring one or more properties at multiple positions within the sample. The system and method can re - image and resolve multiple optical paths within the sample, including selecting a target (e.g., pre - determined) measurement path length such that the spectral signal quality measured by the detector can accurately represent one or more properties of the sample. The system can be configured to be suitable for a compact (e.g., volume less than 1 cm 3Single - layer or double - layer optical devices of the system. The optical devices can be simplified to reduce the number and complexity of coated optical surfaces, etalon effects, manufacturing tolerance stacking issues, and interference - based spectral errors. The optical devices can be formed such that the number of moving parts can be reduced or moving parts can be avoided, and robustness can be enhanced. Additionally, the size, number, and position of the optical devices can enable multiple simultaneous or non - simultaneous measurements at various locations across and within the sample, which can reduce the impact of any non - uniformities in the sample. Further, the system can be configured with an optical spacer window located between the sample and the optical devices, and methods for accounting for the optical path changes due to the inclusion of the optical spacer window are disclosed. Description of the Drawings

[0006] Figure 1A A block diagram of an exemplary system capable of measuring one or more properties at multiple locations within a sample, according to an example of the present disclosure.

[0007] Figure 1B An exemplary processing flow for measuring one or more properties at multiple locations within a sample, according to an example of the present disclosure.

[0008] Figure 2 A cross - sectional view of an exemplary system configured to determine one or more properties of a sample, according to an example of the present disclosure.

[0009] Figure 3 A cross - sectional view of an exemplary system configured to determine one or more properties of a sample, according to an example of the present disclosure.

[0010] Figure 4A A cross - sectional view of an exemplary portion of a system configured to resolve multiple incident angles on a sample surface using a double - layer optical device, according to an example of the present disclosure.

[0011] Figure 4B An exemplary coupler coupled to a light source, according to an example of the present disclosure.

[0012] Figure 4C An exemplary waveguide coupled to a light source, according to an example of the present disclosure.

[0013] Figures 4D to 4H A cross - sectional view of an exemplary optical device layer included in a system configured to resolve multiple optical paths in a sample, according to an example of the present disclosure.

[0014] Figure 4I A cross - sectional view of a portion of an exemplary system configured to resolve multiple incident angles on a sample surface and reduce or eliminate trapped light from a light source, according to an example of the present disclosure.

[0015] Figure 5 A cross-sectional view of a portion of an exemplary system in accordance with an example of the present disclosure is shown, the system being configured to resolve multiple angles of incidence on a sample surface using a single-layer optical device.

[0016] Figure 6 A cross-sectional view of a portion of an exemplary system in accordance with an example of the present disclosure is shown, the system being configured to resolve the lengths of multiple optical paths using a double-layer optical device.

[0017] Figure 7 A cross-sectional view of a portion of an exemplary system in accordance with an example of the present disclosure is shown, the system being configured to resolve the lengths of multiple optical paths using a single-layer optical device.

[0018] Figure 8 Snell's law in accordance with an example of the present disclosure is shown.

[0019] Figures 9A to 9B A top view and a perspective view of an exemplary group including an optical device unit in accordance with an example of the present disclosure are shown.

[0020] Figure 9C A top view of an exemplary plurality of groups including an optical device unit and a detector array in a system in accordance with an example of the present disclosure is shown.

[0021] Figure 10 An exemplary configuration of a ray having a spatial resolution uncertainty in accordance with an example of the present disclosure is shown.

[0022] Figure 11 An exemplary configuration of a ray having an angular resolution uncertainty in accordance with an example of the present disclosure is shown.

[0023] Figure 12 An exemplary configuration of an input beam having a Gaussian angular divergence in accordance with an example of the present disclosure is shown.

[0024] Figure 13A A cross-sectional view of an exemplary system in accordance with an example of the present disclosure is shown, the system including an optical spacer window and a pore layer located between the optical device unit and the sample.

[0025] Figure 13B A cross-sectional view of an exemplary system in accordance with an example of the present disclosure is shown, the system including an optical spacer window located between the optical device unit and the sample.

[0026] Figure 14A A cross-sectional view of an exemplary system not including an optical spacer window in accordance with an example of the present disclosure and correspondingly determining the lateral position of light incident at an external interface of the system (e.g., the interface where the system contacts the sample).

[0027] Figures 14B to 14C A cross-sectional view of an exemplary system including an optical spacer window according to an example of the present disclosure is shown, and accordingly, the lateral position of light incident at an outer interface of the system (e.g., the interface where the system contacts a sample) is determined.

[0028] Figures 14D to 14E A cross-sectional view of an exemplary system including an optical spacer window according to an example of the present disclosure is shown. Detailed Description

[0029] Cross-Reference to Related Applications

[0030] This patent application claims the benefit of priority of U.S. Provisional Patent Application No. 62 / 325,908, filed on April 21, 2016, which is hereby incorporated by reference in its entirety.

[0031] In the following description of the examples, reference will be made to the accompanying drawings, in which specific examples that may be implemented are shown by way of illustration. It should be understood that other examples may be used and structural changes may be made without departing from the scope of the various examples.

[0032] Representative applications of the methods and apparatuses according to the present disclosure are described in this section. These examples are provided only to add context and assist in understanding the examples. Thus, it will be apparent to those skilled in the art that the examples may be practiced without some or all of the specific details. Other applications are possible, such that the following examples should not be considered limiting.

[0033] Various techniques and process flow steps will now be described in detail with reference to the examples as shown in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects and / or features described or mentioned therein. However, it will be apparent to those skilled in the art that one or more aspects and / or features described or mentioned may be implemented without some or all of these specific details. In other instances, well-known process steps and / or structures are not described in detail so as not to obscure some of the aspects and / or features described or mentioned herein.

[0034] The present disclosure relates to systems and methods for determining one or more properties of a sample. The system can include a light source, optics, a reference object, a detector array, and a controller (and / or logic). The disclosed systems and methods are capable of making measurements along multiple positions within the sample to determine one or more properties. The systems and methods can re-image and resolve multiple optical paths within the sample, including selecting a target (e.g., pre-determined) measurement path length such that the quality of the spectral signal measured by the detector can accurately represent one or more properties of the sample. The system can be configured with a single- or double-layer optic suitable for a compact (e.g., having a volume less than 1 cm 3 3) system. The optics can be simplified to reduce the number and complexity of coated optical surfaces, etaloning effects, manufacturing tolerance stacking issues, and interference-based spectral errors. The optics can be formed such that the number of moving parts can be reduced or moving parts can be avoided, and robustness can be enhanced. Additionally, the size, number, and position of the optics can enable multiple simultaneous or non-simultaneous measurements across the sample and at various positions within the sample, which can reduce the impact of any non-uniformities in the sample. Further, the system can be configured with an optical spacer window located between the sample and the optics, and methods for accounting for optical path changes due to the inclusion of the optical spacer window are disclosed.

[0035] Absorption spectroscopy is an analytical technique that can be used to determine one or more properties of a sample. Light can have an initial intensity or energy when it exits the light source and impinges on the sample. As the light transmits through the sample, a portion of the energy can be absorbed at one or more wavelengths. This absorption can cause a change (or loss) in the intensity of the light exiting the sample. The light exiting the sample can be attributed to light scattered from one or more positions within the sample, where the position can include the substance of interest. In some examples, the substance of interest can be present in some or all of the paths of the light entering and / or exiting the sample, where the measured absorbance can include absorption at one or more regions of light scattering. As the concentration of the substance of interest in the sample increases, the amount of light exiting the sample can exponentially decrease. In some examples, the substance can include one or more chemical components, and the concentration of each chemical component present in the sample can be determined using the measurements.

[0036] Figure 1A A block diagram of an exemplary system is shown, and Figure 1BShows an exemplary processing flow for measuring one or more substances at multiple locations within a sample according to an example of the present disclosure. System 100 may include interface 180, optics 190, light source 102, detector 130, and controller 140. Interface 180 may include input region 182, interface reflected light 184, reference object 108, and output region 156. In some examples, input region 182 and / or output region 156 may include a pore layer that includes one or more openings configured to limit the position and / or angle of light leaving and / or entering the system. By limiting the position and / or angle of light leaving and / or entering the system, the light incident on sample 120 or exiting from the sample can also be limited. Optics 190 may include absorber or light blocker 192, optics 194 (e.g., negative microlens), and light collecting optics 116 (e.g., positive microlens). Sample 120 may be located near, adjacent to, or in contact with at least a portion of system 100. Light source 102 may be coupled to controller 140. Controller 140 may send a signal (e.g., a current or voltage waveform) to control light source 102 to emit light towards the surface of sample 120 (step 153 of process 151). Depending on whether the system is measuring one or more properties of the sample or the reference object, light source 102 may emit light towards input region 182 (step 155 of process 151) or reference object 108.

[0037] Input region 182 may be configured to allow light to leave system 100 to be incident on sample 120. The light may penetrate a certain depth into sample 120 and may be reflected and / or scattered back into system 100 (step 157 of process 151). The reflected and / or scattered light may return to system 100 at output region 156 (step 159 of process 151). The reflected and / or scattered light returning to system 100 may be collected by light collecting optics 116, which may redirect, collimate, focus, and / or magnify the reflected and / or scattered light (step 161 of process 151). The reflected and / or scattered light may be directed towards detector 130. Detector 130 may detect the reflected and / or scattered light and may send an electrical signal indicative of the light to controller 140 (step 163 of process 151).

[0038] Additionally or alternatively, the light source 102 may emit light towards the reference object 108 (step 165 of process 151). The reference object 108 may reflect the light towards the optical device 194 (step 167 of process 151). The reference object 108 may include, but is not limited to, a mirror, a filter, and / or a sample having known optical properties. The optical device 194 may redirect, collimate, focus, and / or magnify the light towards the detector 130 (step 169 of process 151). The detector 130 may measure the light reflected from the reference object 108 and may generate an electrical signal indicative of the reflected light (step 171 of process 151). The controller 140 may be configured to receive an electrical signal indicative of the light reflected / scattered from the sample 120 and an electrical signal indicative of the light reflected from the reference object 108 of the detector 130. The controller 140 (or another processor) may determine one or more properties of the sample from the electrical signals (step 173 of process 151).

[0039] In some examples, when the system is measuring one or more substances in the sample and the reference object, the light emitted from the light source 102 may be reflected back to the system 100 from the surface of the sample. The light reflected from the external interface of the system (e.g., the interface where the system contacts the sample) may be referred to as interface-reflected light 184. In some examples, the interface-reflected light 184 may be the light emitted from the light source 102 that is not reflected from the sample 120 or the reference object 108 and may be attributed to light scattering. Since the interface-reflected light 184 may be undesirable, the absorber or light blocker 192 may prevent the interface-reflected light 184 from being collected by the optical device 194 and the light collection optics 116, which may prevent the interface-reflected light 184 from being measured by the detector 130.

[0040] Figure 2A cross-sectional view of an exemplary system configured to determine one or more properties of a sample in accordance with an example of the present disclosure is shown. System 200 may be proximate to, in contact with, resting on, or attached to sample 220. Sample 220 may include one or more locations, such as location 257 and location 259. System 200 may include light source 202. Light source 202 may be configured to emit light 250. Light source 202 may be any source capable of generating light, including but not limited to lamps, lasers, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), electroluminescent (EL) sources, quantum dot (QD) light emitters, superluminescent diodes, supercontinuum sources, fiber-based sources, or a combination of one or more of these sources. In some examples, light source 202 is capable of emitting light of a single wavelength. In some examples, light source 202 is capable of emitting light of multiple wavelengths. In some examples, light source 202 may be any tunable source capable of generating SWIR features. In some examples, multiple light sources may be included in the system, where each light source 202 emits light in a different wavelength range (e.g., different colors in the spectrum). In some examples, light source 202 may include III-V materials such as indium phosphide (InP), gallium antimonide (GaSb), gallium indium antimonide arsenide (GaAsSb), aluminum arsenide (AlAs), aluminum gallium arsenide (AlGaAs), aluminum indium arsenide (AlInAs), indium gallium phosphide (InGaP), indium gallium arsenide (InGaAs), indium antimonide arsenide (InAsSb), indium phosphide antimonide (InPSb), indium antimonide arsenide phosphide (InAsPSb), and gallium indium antimonide arsenide phosphide (GaInAsSbP).

[0041] System 200 may include input region 282, which is proximate to or in the vicinity of sample 220 or on an outer surface of the system. Input region 282 may include one or more transparent components, including but not limited to windows, optical shutters, or mechanical shutters.

[0042] Light 250 can exit the system 200 through the input region 282. In some examples, light 250 can be a collimated beam. The light that exits the system 200 and travels through the sample 220 to reach the location 257 can be referred to as light 252. Light 252 can be incident on the location 257 at any angle, including but not limited to 45°. In some examples, light 252 can have an incident angle between 20° and 30° at the location 257. In some examples, light 252 can have an incident angle of 35° at the location 257. The location 257 can include one or more properties of the sample 220. Light 252 can be partially absorbed before reaching the location 257, at the location 257, and / or after being partially reflected and / or scattered at the location 257, and can be referred to as light 254. In some examples, light 254 can be formed by the light that transmits through the sample 220. Light 254 can penetrate the sample 220 and can enter the system 200 at the location 213 of the optical device 210. In some examples, the optical device 210 can be in contact with or near the sample 220. In some examples, the optical device 210 can be any type of optical component, such as a window. In some examples, the optical device 210 can be any optical component capable of changing the behavior and properties of the incident light, such as a lens. In some examples, the optical device 210 can include a transparent material. The optical device 210 can include multiple locations, including the location 213 and the location 217, where light can enter. In some examples, the optical device 210 can be a lens configured with a large aperture (e.g., the aperture is larger than the size of the incident beam) and a short focal length (e.g., the focal length can focus the sample within a range of 10 mm from the system). In some examples, the optical device 210 can be a silicon lens or a lens including silicon dioxide.

[0043] System 200 may include optics for magnifying or re-imaging an incident light beam. The optics in System 200 are capable of re-imaging an optical path that includes a path length, an incident angle, and an exit location to another plane closer to detector array 230. To reduce any differences in fluctuations, drifts, and / or variations between the optical path that penetrates sample 220 (e.g., light 252 or light 253) and the optical path that reflects off reference object 222 (e.g., reflector), System 200 may share optics between two different optical paths. System 200 may include optics 210, optics 216, and / or optics 218 for re-imaging light that has penetrated the sample and light that has not penetrated sample 220. In some examples, optics 216 and optics 218 may be configured such that re-imaging of the incident optical path at the external interface of the system (e.g., the interface where the system contacts the sample) can be re-imaged onto another plane (e.g., the plane where detector array 230 is located) without magnification. In some examples, optics 216 and optics 218 may be configured such that magnification (such as 2.5x to 5x magnification) is introduced into the image.

[0044] Light 254 may transmit through optics 216 and optics 218 and may be incident on optics 223. Optics 223 may be included in optics unit 229. Optics unit 229 may include a plurality of optics attached to a substrate, such as optics 223 and optics 227. In some examples, the optics may be of any type and may include any type of material conventionally used in optics. In some examples, two or more optics may have the same optical (e.g., reflectivity, refractive index, and transparency range) and / or geometric properties (e.g., curvature / focal length or pitch). Those skilled in the art will understand that the same optical properties and the same geometric properties may include tolerances that result in a 15% deviation. In some examples, optics unit 229 may be coupled to one or more pore layers. In some examples, optics unit 229 may be coupled to a patterned pore layer, such as a pore layer where the locations between adjacent optics are opaque to prevent light mixing.

[0045] Light 254 can be transmitted through the optical device 223, and the optical device 223 can converge the light 254 to be detected by the detector pixels 233 included in the detector array 230. In some examples, the optical device 223 can converge the light 254 to the center position (not shown) or the edge position of the detector pixel. The detector array 230 can include one or more detector pixels, such as detector pixels 233, detector pixels 235, and detector pixels 237 disposed on a substrate. The detector pixels can include one or more detector elements having a common device package (e.g., the same size and shape). The detector element can be an element designed to detect the presence of light and can individually generate a signal representing the detected light. In some examples, at least one detector pixel can be independently controlled (e.g., measured, observed, or monitored) from other detector pixels in the detector array 230. In some examples, at least one detector pixel is capable of detecting light in the short-wave infrared (SWIR) range. In some examples, at least one detector pixel can be a SWIR detector capable of operating between 2.0 - 2.5 μm. In some examples, at least one detector pixel can be a detector based on HgCdTe, InSb, or InGaAs. In some examples, at least one detector pixel can be associated with a particular sample position and / or the angle of light incident on the surface of the system 200. The detector pixel 233 can detect the light 254 and can generate an electrical signal indicating the properties of the detected light 254. The detector array 230 can transmit the electrical signal to the controller 240, and the controller 240 can process and / or store the electrical signal.

[0046] System 200 can determine one or more properties of sample 220 by leveraging information from light reflected from the sample and information from light reflected off a reference object 222, such as a reflector. Light source 202 can emit light 264. Light 264 can be directed toward reference object 222. Reference object 222 can include any type of material capable of at least partially reflecting incident light. Exemplary reflective materials can include, but are not limited to, titanium (Ti), cobalt (Co), niobium (Nb), tungsten (W), nickel chromium (NiCr), titanium tungsten (TiW), chromium (Cr), aluminum (Al), gold (Au), and silver (Ag). In some examples, the reflective material can include one or more dielectric layers. One or more properties (e.g., thickness) of reference object 222 can be determined based on the wavelength of the light, the type of material, and / or the composition of reference object 222. In some examples, the size and shape of reference object 222 can be configured to be greater than or equal to the size and / or shape of the light beam of light 264. Those skilled in the art will understand that the same size and shape can include tolerances that result in a 15% deviation. In some examples, the optical and / or physical properties of reference object 222 can be such that the reflectivity of light 264 is greater than 75%. In some examples, the optical and / or physical properties of reference object 222 can be such that the reflectivity of light 264 can be greater than 90%. In some examples, the size and shape of reference object 222 can be such that less than 15% of light 264 is allowed to transmit through reference object 222 and prevent light 264 from reaching sample 220. In some examples, reference object 222 can be configured to reflect light 264 as specular reflection. In some examples, reference object 222 can be a spectral neutral blocker. In some examples, the reference signal can include chopped light 264 between light 252 entering sample 220 and light 264 incident on reference object 222. Although Figure 2 reference object 222 is shown at an external interface of the system (e.g., the interface where the system contacts the sample), examples of the present disclosure can include reference objects located at other positions, including but not limited to the inner walls of the system, the sides of optical devices, and the like.

[0047] Light 264 can be reflected away from reference object 222 towards optical device 216. Light 264 can be transmitted through optical device 216 towards optical device 218. Light 264 can be transmitted through optical device 218 and can be incident on optical device 219 included in optical device unit 229. Optical device 219 can be any type of optical device configured to diffuse an incident light beam. In some examples, optical device 219 can be a negative lens, which can be a lens with a negative focal length. In some examples, optical device 219 can be a prism. In some examples, optical device 219 can include a prism wedge angled for each detector pixel in detector array 230. In some examples, optical device 219 can be a beam splitter. In some examples, optical device 219 can be configured to diffuse or split light into multiple light beams, such as light 266 and light 267. In some examples, optical device 219 can diffuse light such that each light beam can be directed to a different detector pixel in detector array 230. In some examples, optical device 219 can diffuse light uniformly such that each light beam can have the same properties. Those skilled in the art will understand that the same properties can include tolerances that result in a 15% deviation. In some examples, optical device 219 can diffuse light such that the intensities of at least two light beams are different. In some examples, optical device 219 can include multiple optical devices. In some examples, the size and / or shape of optical device 219 can be based on the number of detector pixels to which the light is diffused, the properties of one or more light beams leaving optical device 219, or both. In some examples, a pore layer can be coupled to optical device 219 to control the properties and / or direction of light exiting optical device 219. In some examples, optical device 219 or system 200 can be configured such that light reflected back from the sample surface to the system (i.e., light that does not penetrate sample 220) is prevented from being incident on optical device 219, but stray light or background light can be incident on optical device 219.

[0048] Light 264 can be transmitted through the optical device 219 to form light 266. Light 266 can be incident on the detector pixel 233. The detector pixel 233 can detect light 266 and can generate an electrical signal indicative of the properties of the detected light 266. In some examples, the number of detector pixels configured to detect a light beam can be different for different light beams. For example, light 255 can be detected by two detector pixels (e.g., detector pixel 235 and detector pixel 237), while light 254 can be detected by one detector pixel (e.g., detector pixel 233). The electrical signal can be transmitted from the detector array 230 to the controller 240. The controller 240 can process and / or store the electrical signal. The controller 240 can utilize the signal information measured from light 254 to determine the reflectivity or one or more sample properties along the optical path directed to the location 257, and can utilize the signal information from light 266 to detect any fluctuations or drifts in the light source 202 and / or the detector array 230. By using any of the above methods, the controller 240 can process the electrical signal and the signal information to determine one or more properties of the sample 220.

[0049] The same components in the system 200 can be used for measurements at other locations (such as location 259) in the sample 220. Light 252 that is not absorbed or reflected along the optical path directed to the location 257 can be referred to as light 253. Light 253 can be incident on the location 259 and can be reflected and / or scattered into the system 200 as light 255. In some examples, the angle of incidence of light 255 at the surface of the system 200 can be different from the angle of incidence of light 254. Light 255 can enter the system 200 through the optical device 210 at the location 217. Light 255 can be transmitted through the optical devices 216 and 218 and can be incident on the optical device 227 included in the optical device unit 229. Light 255 can be transmitted through the optical device 227, and the optical device 227 can converge, redirect, collimate, focus, and / or magnify the light such that the light 255 is detected by the detector pixels 235 and 237 included in the detector array 230. The detector pixels 235 and 237 can detect light 255 and can generate an electrical signal indicative of the properties of the detected light 255. In some examples, the optical device 227 can converge, redirect, collimate, focus, and / or magnify the light such that the light 255 is incident on the central or edge position of the detector pixel. Any number of detector pixels can be configured to detect the light beam. The detector array 230 can transmit the electrical signal to the controller 240. The controller 240 can process and / or store the electrical signal.

[0050] The controller 240 can utilize the signal information measured from the light 255 to determine one or more properties of the sample 220, and can utilize the signal information from the light 267 to detect any fluctuations or drifts in the light source 202 and / or the detector array 230. In some examples, the controller 240 can simultaneously detect the light 266 incident on the detector pixel 233 and the light 267 incident on the detector pixel 235 and / or the detector pixel 237 without the need for separate measurements. In some examples, the positions 257 and 259 can have the same depth from the surface of the sample 220 or the external interface of the system (e.g., the interface where the system contacts the sample). Those skilled in the art will understand that the same depth can include a tolerance that results in a 15% deviation. In some examples, the positions 257 and 259 can have different depths from the surface of the sample 220. The controller 240 can measure the reflectivity, refractive index, density, concentration, scattering coefficient, scattering anisotropy, or absorbance at the positions 257 and 259, and can average these values.

[0051] Although the above figures and discussion relate to two positions in the sample, examples of the present disclosure can include any number of positions and are not limited to one or two positions. In some examples, light can be incident on multiple positions at the same angle of incidence. In some examples, the light source can be configured to generate one beam that exits the system, which causes multiple incoming beams to be reflected and / or scattered back into the system. In some examples, the system can be configured with one or more light sources that emit light at positions having different angles of incidence, where the light can be emitted simultaneously or at different times.

[0052] In some examples, the system 200 can further include a light blocker 292. The light blocker 292 can include any material capable of absorbing or blocking light. In some examples, the light blocker 292 can include any material that prevents the reflection of incident light (e.g., an anti-reflection coating). That is, the light blocker 292 can prevent unwanted light from reaching the detector array 230 and being measured by it. In some examples, the light blocker 292 can include any material that reflects at a wavelength different from the detection wavelength of the detector array 230.

[0053] As shown, system 200 may include a plurality of optical devices and a plurality of detector pixels, where each optical device may be associated with one or more detector pixels. Each optical device-detector pixel pair may be associated with an optical path in sample 220. In some examples, the association may be an association of an optical device-detector pixel pair with an optical path in sample 220. For example, optical device 223 and detector pixel 233 may be associated with an optical path from light 254, and optical device 227 and detector pixel 237 may be associated with an optical path from light 255. Since controller 240 may associate detection pixel 233 and detection pixel 237 with different locations (e.g., location 257 and location 259) and / or different optical paths in sample 220, controller 240 may discern differences in path length, penetration depth, angle of incidence, exit location, and / or angle of exit.

[0054] Figure 3 A cross-sectional view of an exemplary system configured to determine one or more properties of a sample in accordance with an example of the present disclosure is shown. System 300 may be proximate to, in contact with, resting on, or attached to the surface of sample 320. Sample 320 may include one or more locations, such as location 357 and location 359. In some examples, one or more locations may be associated with one or more scattering events.

[0055] System 300 may include light source 302. Light source 302 may be configured to emit light 350. Light source 302 may be any source capable of generating light, including but not limited to lamps, lasers, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), electroluminescent (EL) sources, quantum dot (QD) light emitters, superluminescent diodes, supercontinuum sources, fiber-based sources, or a combination of one or more of these sources. In some examples, light source 302 is capable of emitting light of a single wavelength. In some examples, light source 302 is capable of emitting light of multiple wavelengths. In some examples, light source 302 may be any tunable source capable of generating SWIR features. In some examples, a plurality of light sources may be included in the system, where each light source 302 emits light in a different wavelength range (e.g., different colors in the spectrum). In some examples, light source 302 may include III-V materials such as indium phosphide (InP), gallium antimonide (GaSb), gallium indium antimonide (GaAsSb), aluminum arsenide (AlAs), aluminum gallium arsenide (AlGaAs), aluminum indium arsenide (AlInAs), indium gallium phosphide (InGaP), indium gallium arsenide (InGaAs), indium antimonide arsenide (InAsSb), indium phosphide antimonide (InPSb), indium antimonide arsenide phosphide (InAsPSb), and gallium indium antimonide arsenide phosphide (GaInAsSbP).

[0056] System 300 may also include an input region 382 or an outer surface of the system that is near or in the vicinity of the sample 320. The input region 382 may include one or more transparent components, including but not limited to windows, optical shutters, or mechanical shutters.

[0057] Light 350 may exit the system 300 through the input region 382. In some examples, the light 350 may be a collimated beam. The light that exits the system 300 and travels through the sample 320 to reach the location 357 may be referred to as light 352. The light 352 may be incident on the location 357 at any angle, including but not limited to 45°. In some examples, the light 352 may have an incident angle between 20° and 30° at the location 357.

[0058] In some examples, the light 352 may have an incident angle of 35° at the location 357. The location 357 may include one or more properties of the sample 320. The light 352 may be partially absorbed before reaching the location 357, at the location 357, and / or after being partially reflected and / or scattered at the location 357, and may be referred to as light 354. In some examples, the light 354 may be formed by the light that transmits through the sample 320. The light 354 may penetrate the sample 320 and may enter the system 300 at the location 313 of the optical device 310. In some examples, the optical device 310 may be in contact with or in the vicinity of the sample 320. The optical device 310 may be any type of optical component capable of changing the behavior and properties of the incident light, such as a lens. The optical device 310 may include multiple locations, such as the location 313 and the location 317, where the light exiting the sample 320 is allowed to enter the system 300. In some examples, the optical device 310 may include a transparent material. In some examples, the optical device 310 may be a lens configured with a large aperture (e.g., the aperture is larger than the size of the incident beam) and a short focal length (e.g., the focal length may be such that the sample 220 within 10 mm of the system is focused). In some examples, the optical device 310 may be a silicon lens or a lens including silicon dioxide.

[0059] System 300 may include optics, such as optics 316 and optics 318. In some examples, optics 316 and optics 318 may be objective lenses. An objective lens is a lens that can collect incident light and magnify a light beam while having a short focal length. Optics 316 may collect light 354 and direct light 354 toward an opening 385 included in a pore layer 386. The pore layer 386 may include one or more openings, such as opening 385 and opening 387, and the one or more openings are configured to allow light to transmit therethrough. The pore layer 386 is capable of selecting light having one or more specific path lengths, incident angles, or both, and rejecting or attenuating light having other path lengths or incident angles. The selection and rejection of light based on path length, incident angle, or both can be optimized by adjusting the pore size (i.e., the size of the openings in the pore layer). The selected light (i.e., light having one or more specific path lengths, incident angles, or both) may be focused when reaching the openings in the pore layer, and the rejected light may be defocused. The defocused light may have a beam size greater than the pore size, may have an incident angle outside the collection range, or both, and thus can be rejected. The focused light may have a beam within the path length range and the collection angle range and thus can be allowed to transmit through the pore layer.

[0060] The light 354 exiting the opening 385 in the pore layer 386 may transmit through optics 318 and may be incident on optics 323. Optics 323 may be included in an optics unit 39. The optics unit 39 may include a plurality of optics attached to a substrate, such as optics 323 and optics 327. In some examples, the optics may be of any type and may include any type of material conventionally used in optics. In some examples, two or more optics may have the same optical and / or geometric properties. Those skilled in the art will understand that the same optical properties and the same geometric properties may include tolerances that result in a 15% deviation. In some examples, the optics unit 39 may be coupled to one or more pore layers. In some examples, the optics unit 39 may be coupled to a patterned pore layer, such as a pore layer where the positions between adjacent optics are opaque to prevent light mixing.

[0061] Light 354 can be transmitted through the optical device 323 and can be incident on the detector pixels 333 included in the detector array 330. The detector array 330 can include a plurality of detector pixels, such as detector pixel 333, detector pixel 335, and detector pixel 337. The detector pixels can include one or more detector elements having a common device package (e.g., the same size and shape). The detector elements can be elements designed to detect the presence of light and can individually generate signals representative of the detected light. In some examples, at least one detector pixel can be controlled (e.g., measured, observed, or monitored) independently from other detector pixels in the detector array 330. In some examples, at least one detector pixel is capable of detecting light in the SWIR range. In some examples, at least one detector pixel can be a SWIR detector capable of operating between 1.5 - 2.5 μm. In some examples, at least one detector pixel can be a detector based on HgCdTe, InSb, or InGaAs. In some examples, at least one detector pixel can be associated with a particular sample location and / or the angle of light incident on the surface of the system 300. The detector pixel 333 can detect the light 354 and can generate an electrical signal indicative of the properties of the detected light 354. The detector array 330 can transmit the electrical signal to the controller 340, and the controller 340 can process and / or store the electrical signal.

[0062] System 300 can determine one or more properties in sample 320 by leveraging information from light that penetrates sample 320 (and reflects away from a location within the sample) and information from light that reflects away from reference object 322. Light source 302 can emit light 364. Light 364 can be directed toward reference object 322. Reference object 322 can include any type of material capable of at least partially reflecting light. Exemplary reflective materials can include, but are not limited to, Ti, Co, Nb, W, NiCr, TiW, Cr, Al, Au, and Ag. In some examples, the reflective material can include one or more dielectric layers. One or more properties (e.g., thickness) of the reference object can be determined based on the wavelength of the light, the type of material, and / or the composition of reference object 322. In some examples, the size and shape of reference object 322 can be configured to be greater than or equal to the size and / or shape of light 364. Those skilled in the art will understand that the same size and the same shape can include tolerances that result in a 15% deviation. In some examples, the optical and / or physical properties of reference object 322 can be such that the reflectivity of light 364 is greater than 75%. In some examples, the optical and / or physical properties of reference object 322 can be such that the reflectivity of light 364 is greater than 90%. In some examples, the size and shape of reference object 322 can be such that less than 15% of light 364 is allowed to transmit through reference object 322 and prevent light 364 from reaching sample 320. In some examples, reference object 322 can be configured to reflect light 364 as specular reflection. In some examples, reference object 322 can be a spectral neutral blocker. In some examples, the reference signal can include chopped light 364 between sample 320 and reference object 322.

[0063] Light 364 can be reflected away from reference object 322 towards optical device 316. Light 364 can be transmitted through optical device 316 towards pore layer 386. Pore layer 386 can be configured with an opening 389, the size and shape of which can be configured to allow light 364 to be transmitted through. Light 364 leaving opening 389 can be incident on optical device 318. Light 364 can be transmitted through optical device 318 and incident on optical device 319. Optical device 319 can be any type of optical device configured to diffuse an incident light beam. In some examples, optical device 319 can be a negative lens, which is a lens with a negative focal length. In some examples, optical device 319 can be a prism. In some examples, optical device 319 can include a prism wedge angled for each detector pixel in detector array 330. In some examples, optical device 319 can be a beam splitter. In some examples, optical device 319 can be configured to diffuse or split light into multiple light beams, such as light 366 and light 367. In some examples, optical device 319 can diffuse light such that each light beam is directed to a different detector pixel on detector array 330. In some examples, optical device 319 can diffuse light evenly such that one or more properties of each light beam are the same. Those skilled in the art will understand that the same properties can include tolerances that result in a 15% deviation. In some examples, optical device 319 can diffuse light beams such that the intensities of at least two light beams are different. In some examples, optical device 319 can include multiple optical devices. In some examples, the size and / or shape of optical device 319 can be based on the number of detector pixels and / or the properties of one or more light beams leaving optical device 319. In some examples, the pore layer can be coupled to optical device 319 to control the properties and / or direction of light exiting optical device 319.

[0064] Light 364 can transmit through the optical device 319 to form light 366. The light 366 can be incident on the detector pixel 333. The detector pixel 333 can detect the light 366 and can generate an electrical signal indicating the properties of the detected light 366. In some examples, the number of detector pixels configured to detect a light beam can be different for different light beams. For example, the light 355 can be detected by two detector pixels (e.g., detector pixel 335 and detector pixel 337), while the light 354 can be detected by one detector pixel (e.g., detector pixel 233). The electrical signal can be transmitted from the detector array 330 to the controller 340. The controller 340 can process and / or store the electrical signal. The controller 340 can utilize the signal information measured from the light 354 to determine the reflectivity or one or more properties along the optical path guided to the location 357, and can utilize the signal information from the light 366 to detect any fluctuations or drifts in the light source 302 and / or the detector array 330. By using any of the above methods, the controller 340 can process both the electrical signal and the signal information to determine one or more properties of the sample 320.

[0065] The same components can be used for measurements at other locations (such as location 359) in sample 320. Light 352 that is not absorbed or reflected along the optical path directed to location 357 can be referred to as light 353. Light 353 can be incident on location 359 and can be reflected and / or scattered into system 300 as light 355. In some examples, the angle of incidence of light 355 at the surface of system 300 can be different from the angle of incidence of light 354. Light 355 can enter system 300 through the optical device 310 at location 317. Light 355 can transmit through the optical device 316 and can be incident on the pore layer 386. The pore layer 386 can include an opening 387 that is configured to allow light 355 (and any light having the same path length, angle of incidence, or both) to transmit through. Those skilled in the art will understand that the same path length and the same angle of incidence can include tolerances that result in a 15% deviation. In some examples, since the light reflected from location 357 can have a different path length from the light reflected from location 359, the pore layer 386 can include multiple openings having different sizes and / or shapes to account for the different properties of the optical paths (e.g., path length and angle of incidence). For example, the opening 385 can be configured with dimensions and a shape based on the path length and angle of incidence of light 354, and the opening 387 can be configured with dimensions and a shape based on the path length and angle of incidence of light 355. Light 355 can transmit through the opening 387 in the pore layer 386, can transmit through the optical device 318, and can be incident on the optical device 327 included in the optical device unit 39. Light 355 can transmit through the optical device 327, and the optical device 327 can converge, redirect, collimate, focus, and / or magnify the light such that the light 355 is detected by the detector pixels 335 and the detector pixels 337. The detector pixels 335 and the detector pixels 337 can detect the light 355 and can generate an electrical signal indicative of the properties of the detected light 355. The detector array 330 can transmit the electrical signal to the controller 340, and the controller 340 can process and / or store the electrical signal.

[0066] The controller 340 can utilize the signal information measured from the light 355 to determine one or more properties of the sample 320, and can utilize the signal information from the light 367 to detect any fluctuations or drifts in the light source 302 and / or the detector array 330. The controller 340 can process the two sets of signal information to determine one or more properties along the optical path that is directed to the location 359 within the sample 320. In some examples, the controller 340 can simultaneously detect the light 366 incident on the detector pixel 333 and the light 367 incident on the detector pixels 335 and 337 without the need for separate measurements. In some examples, the locations 357 and 359 can have the same depth from the surface of the sample 320. Those skilled in the art will understand that the same depth can include a tolerance that results in a 15% deviation. In some examples, the locations 357 and 359 can have different depths from the surface of the sample 320. The controller 340 can measure the reflectivity, refractive index, density, concentration, scattering coefficient, scattering anisotropy, or absorbance at the locations 357 and 359 and can average these values.

[0067] Although the above figures and discussion relate to two locations in the sample, examples of the present disclosure can include any number of locations and are not limited to one or two locations. In some examples, light can be incident on multiple locations at the same angle of incidence. In some examples, the light source can be configured to generate one beam that exits the system, which results in multiple incoming beams being reflected and / or scattered back into the system. In some examples, the system can be configured with one or more light sources that emit light at locations having different angles of incidence, where the light can be emitted simultaneously or at different times.

[0068] As shown, the system 300 can include multiple openings in the aperture, multiple optical devices, and multiple detector pixels, where each opening and optical device can be coupled to a detector pixel. Each opening / optical device / detector pixel triad can be associated with an optical path in the sample 320. In some examples, the association can be an association between one opening-optical device-detector pixel triad and one optical path in the sample 320. For example, the opening 385, the optical device 323, and the detector pixel 333 can be associated with the optical path from the light 354. Similarly, the opening 387, the optical device 327, and the detector pixel 337 can be associated with the optical path from the light 355. Since the controller can associate the detector pixels 333 and 337 with different locations (e.g., locations 357 and 359) in the sample 320 and different depths or path lengths, the controller 340 can discern differences in path length, penetration depth, angle of incidence, exit location, and / or angle of exit.

[0069] In some examples, system 300 may further include a light blocker 392. The light blocker 392 may include any material capable of absorbing or blocking light. In some examples, the light blocker 392 may include any material that prevents reflection of incident light (e.g., an anti-reflection coating). In some examples, the light blocker 392 may include any material that reflects at a wavelength different from the detection wavelength of the detector array 330.

[0070] Figure 4A A cross-sectional view of an exemplary portion of a system according to an example of the present disclosure is shown, the system being configured to resolve multiple angles of incidence on a sample surface using a bilayer optical device. System 400 may be close to, in contact with, resting on, or attached to sample 420. Sample 420 may include one or more locations, such as location 457. In some examples, one or more locations may be associated with one or more scattering events. System 400 may be configured to re-image the optical path in sample 420. For example, system 400 may be configured to re-image the angle of incident light and the exit position onto another plane (e.g., a plane positioned closer to detector array 430). Re-imaging of the optical path may be performed using one or more layers of optical devices. For example, system 400 may include a bilayer optical device. Below the optical device layer (i.e., opposite the surface of sample 420) may be detector array 430, and the bilayer optical device may be supported by support 414. Between the bilayer optical devices may be air, a vacuum, or any medium having a refractive index that contrasts with the refractive index of the optical devices. Although the drawings show a system including a bilayer optical device, examples of the present disclosure may include, but are not limited to, optical devices including a single layer or any number of layers more than two layers.

[0071] System 400 may include a light source 402. The light source 402 may be configured to emit light 450. The light source 402 can be any source capable of generating light, including but not limited to lamps, lasers, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), electroluminescent (EL) sources, quantum dot (QD) light emitters, superluminescent diodes, supercontinuum sources, fiber-based sources, or a combination of one or more of these sources. In some examples, the light source 402 may be capable of emitting light of a single wavelength. In some examples, the light source 402 may be capable of emitting light of multiple wavelengths. In some examples, the light source 402 can be any tunable source capable of generating SWIR features. In some examples, each of the light sources 402 may emit light in a different wavelength range (e.g., different colors in the spectrum). In some examples, the light source 402 may include III-V materials such as indium phosphide (InP), gallium antimonide (GaSb), gallium arsenide antimonide (GaAsSb), aluminum arsenide (AlAs), aluminum gallium arsenide (AlGaAs), aluminum indium arsenide (AlInAs), indium gallium phosphide (InGaP), indium gallium arsenide (InGaAs), indium arsenide antimonide (InAsSb), indium phosphide antimonide (InPSb), indium arsenide phosphide antimonide (InAsPSb), and gallium indium arsenide antimonide phosphide (GaInAsSbP).

[0072] Light from the light source 402 can be combined using the integrated tuning element 404, optical traces (not shown), and one or more multiplexers (not shown). In some examples, the integrated tuning element 404, optical traces, and multiplexers can be disposed on the substrate 442 or included in a single optical platform such as a silicon photonics chip. The system 400 can also include a thermal management unit 401 for controlling, heating, or cooling the temperature of the light source 402. Coupled to one or more multiplexers can be an output coupler 409. The output coupler 409 can optionally be configured to focus, collect, collimate, and / or condition (e.g., shape) the light beam from the multiplexer toward the optical device 416. In some examples, the output coupler 409 can be configured as a single-mode waveguide that directs a well-defined (i.e., directional) light beam toward the optical device 416. In some examples, the light 450 from the output coupler 409 can be a light beam having any suitable shape (e.g., tapered, cylindrical, etc.). In some examples, the light 450 from the output coupler 409 can become total internal reflection (TIR) or be "trapped" between the substrate 442 and one or two optical device layers. The optical device 416 can receive the light 450 and can collimate and / or tilt the light beam toward one or more locations in the sample 420. In some examples, the optical device 416 can include a flat (or within 10% of flat) bottom surface (i.e., the surface facing the output coupler 409) and a convex top surface (i.e., the surface facing away from the output coupler 409). The light emitted from the light source 402, collimated by the output coupler 409, transmitted through the optical device 416, and then exiting the system 400 can be referred to as light 452.

[0073] In some examples, the output coupler 409 can be coupled to a waveguide included in a junction. Figure 4B An exemplary junction coupled to a light source is shown in accordance with an example of the present disclosure. The junction 403 can be configured to split or divide the light emitted from the light source 402, where a portion of the light can be directed to the waveguide 405 and a portion of the light can be directed to the waveguide 407. The waveguide 405 can be coupled to the output coupler 409, which can direct the light to the sample 420. The waveguide 407 can also be coupled to the output coupler 409, which can direct the light to the reference object 422. In some examples, the light from the light source 402 can split at the junction 403, and the light can split equally between the waveguide 405 and the waveguide 407. In some examples, the junction 403 can be an asymmetric y-shaped junction, and the light can be split such that the intensity of the light passing through the waveguide 405 is greater than the intensity of the light passing through the waveguide 407.

[0074] In some examples, the height and width of waveguide 405, waveguide 407, or both can be configured based on the size and shape of the light beam and the divergence properties. For example, for an elliptical light beam, the aspect ratio of waveguide 405 can be configured to be greater than one. In some examples, the aspect ratio of waveguide 405 can be equal to one, and the shape of the light beam can be circular. In some examples, the aspect ratio of waveguide 405 can be less than one. In some examples, the height of the waveguide can be less than the width of the waveguide, such that the light beam diverges asymmetrically.

[0075] As described above, reference switching can include alternating between transmitting light to sample 420 and transmitting light to reference object 422. Although mechanical moving parts can be used to perform such switching, examples of the present disclosure can include non-moving parts that block light, such as diode 411. Diode 411 can be coupled to source 413, which can be configured to provide a current through waveguide 405. With the current through waveguide 405, electrons in the current can absorb photons in the light traveling through waveguide 405, which can prevent the light from being output from waveguide 405. The light traveling through waveguide 407 can also be adjusted to have another diode 411 coupled to another source 413, which can be configured to provide a current through waveguide 407. In some examples, waveguide 405 and / or waveguide 407 can include a configuration such that current passes through multiple locations along the waveguide, as Figure 4C shown. By passing current through multiple locations along the waveguide, a lower current may be required to be provided from source 413 to block the light, which can result in lower power consumption. Although Figure 4B two diodes are shown (e.g., diode 411 coupled to waveguide 405 and another diode 411 coupled to waveguide 407), examples of the present disclosure can include any number of diodes.

[0076] Referring back to Figure 4A , light 452 can be directed at sample 420 and can be incident on location 457. A portion of light 452, referred to as light 454, can be reflected back and / or scattered into system 400 at an incident angle θ 1 . In some examples, the light 452 leaving system 400 can be a collimated light beam, where one or more scattering events can occur along the optical path being directed to location 457 and can cause light 454 to become a scattered light beam. Light 454 can enter system 400 and can be incident on an optical device 418 included in optical device unit 410. In some examples, light 454 can be a collimated light beam.

[0077] System 400 may include one or more optical units. In some examples, the optical unit may have one or more different functions and / or may include one or more different materials. For example, optical unit 410 may change the general direction of light, while optical unit 429 may focus light. In some cases, optical unit 410 may include a sapphire lens, while optical unit 429 may include a silicon lens.

[0078] Optical unit 410 may include one or more optical devices (e.g., lenses, micro-optical devices, or microlenses) configured to collect incident light, adjust the beam size and shape, and / or focus the incident light. For example, optical device 418 may collect light 454 incident on system 400 at an incident angle θ 1 The optical device 418 may change the angle of the light 454 (i.e., redirect its beam) such that the light 454 is directed toward the optical unit 429 and the incident angle on the optical unit 429 is less than the incident angle θ 1 . In some examples, the medium between the optical unit 410 and the optical unit 429 may be configured to have a refractive index such that the change in the angle (i.e., bending) of the light 454 is reduced. In some examples, the medium may be multifunctional and may include a conformal material that provides mechanical support. In some examples, the optical device 418 may at least partially focus the light 454. In some examples, the optical unit 410 may preferentially collect the light rays included in the light 454, where the incident angle is within the range of the collection angle. In some examples, the optical unit 410 may include multiple silicon lenses. In some examples, the optical unit 410 may include one or more optical devices. Although Figure 4A the optical unit 410 is shown attached to the support 414, examples of the present disclosure may include an optical unit 410 attached to or coupled to the optical unit 429 by mechanical features etched into the optical unit 410, the optical unit 429, or both. In some examples, at least two of the optical devices included in the optical unit 410 may have different geometric properties. A detailed discussion of the properties of the optical devices in the optical unit 410 is provided below.

[0079] System 400 may further include a pore layer 486. The pore layer 486 may include a configuration to allow the light 454 (or having the same incident angle θ 1An opening 487 through which any light) is transmitted. Those skilled in the art will understand that the same incident angle may include a tolerance that results in a 15% deviation. The light 454 that has been transmitted through the opening 487 may be directed to an optical device 423 included in the optical device unit 429. The optical device unit 429 may include a plurality of optical devices attached to a substrate, such as the optical device 423 and the optical device 427. In some examples, the optical device 423 and the optical device 427 may be any type of optical device and may include any type of material commonly used in optical devices. In some examples, two or more of the optical devices in the optical device unit 429 may have the same optical and / or geometric properties. Those skilled in the art will understand that the same optical properties and geometric properties may include a tolerance that results in a 15% deviation. In some examples, the optical device 416 and the optical devices included in the optical device unit 429 (e.g., the optical device 423 and the optical device 427) may be disposed or formed on the same substrate. In some examples, the optical device 416 and the optical device unit 429 may be manufactured simultaneously using lithography and the same etching process. Lithographic patterning may define the alignment of the optical devices, which may reduce the number of alignment steps and the number of separately manufactured components. Although Figure 4A Although the optical device unit 429 attached to the support 414 is shown, examples of the present disclosure may include an optical device unit 429 attached to or coupled to the optical device unit 410 by mechanical features etched into the optical device unit 410, the optical device unit 429, or both. In some examples, at least two of the optical devices included in the optical device unit 429 may have different geometric properties. A detailed discussion of the properties of the optical devices in the optical device unit 429 is provided below.

[0080] The optical device 423 may focus the light 454 toward the detector array 430. In some examples, the light 454 may undergo at least partial refraction from the optical device 418. The optical device 423 may re - collimate the light 454 and focus the light 454. In some examples, the system 400 may be configured such that the light 454 is steered by the optical device unit 410 and focused by the optical device unit 429. In some examples, the system 400 may be configured such that the light 454 is steered by both the optical device unit 410 and the optical device unit 429. In some examples, the optical device unit 429 may include a plurality of silicon micro - optical devices.

[0081] Light 454 can be transmitted through the optical device 423 and detected by detector pixels 433 included in the detector array 430. The detector array 430 can include one or more detector pixels, such as detector pixel 433 and detector pixel 437 disposed on a substrate. In some examples, the substrate can be a silicon substrate. The detector pixels can include one or more detector elements having a common device package (e.g., the same size and shape). The detector elements can be elements designed to detect the presence of light and can individually generate signals representative of the detected light. In some examples, at least one detector pixel can be independently controlled from other detector pixels in the detector array 430. In some examples, at least one detector pixel can be capable of detecting light in the SWIR range. In some examples, at least one detector pixel can be a SWIR detector capable of operating between 1.5 - 2.5 μm. In some examples, at least one detector pixel can be a detector based on HgCdTe, InSb, or InGaAs. In some examples, at least one detector pixel can be capable of detecting the position and / or angle of light incident on the surface of the detector pixel. The detector pixel 433 can be coupled to an integrated circuit, such as a readout integrated circuit (ROIC) 441. Each circuit in the ROIC 441 can store charge corresponding to light (or photons of light) detected on the detector pixel that will be sampled and read out by a processor or controller (not shown) in an integrating capacitor. The stored charge can correspond to one or more optical properties of the light 454 (e.g., absorbance, transmittance, and reflectance). In some examples, the ROIC 441 can be fabricated on a silicon substrate.

[0082] Another portion of the light 452 incident at the location 457 can be at an incident angle θ 3 Reflected back into the system 400 and can be referred to as light 455. The light 455 can enter the system 400 and can be incident on the optical device 419 included in the optical device unit 410. Similar to the optical device 418, the optical device 419 can collect the incident light, adjust the beam size and shape (e.g., redirect the beam), and / or focus the incident light. The light 455 can be transmitted through the opening 489 included in the pore layer 486. The light 455 can be directed towards the optical device 427 included in the optical device unit 429. The optical device 427 can focus the light 455 towards the detector pixel 437 included in the detector array 430. In some examples, the system 400 can be configured such that the light 455 is redirected by the optical device unit 410 and focused by the optical device unit 429. In some examples, the system 400 can be configured such that the light 455 is redirected by both the optical device unit 410 and the optical device unit 429.

[0083] As described above, system 400 may include a plurality of optical devices (e.g., optical device 418 and optical device 419) included in optical device unit 410 and a plurality of optical devices (e.g., optical device 423 and optical device 427) included in optical device unit 429, where each of the optical devices may be coupled to a detector pixel (e.g., detector pixel 433 or detector pixel 437) included in detector array 430. Each first optical device - second optical device - detector pixel triad may be associated with an optical path in sample 420. In some examples, the association may be an association between one first optical device - second optical device - detector pixel triad and one optical path in sample 420. For example, optical device 418, optical device 423, and detector pixel 433 may form a first optical device - second optical device - detector pixel triad associated with the optical path from light 454. Similarly, optical device 419, optical device 427, and detector pixel 437 may form another first optical device / second optical device / detector pixel triad associated with the optical path from light 455. In this way, system 400 is capable of re - imaging and resolving multiple optical paths in sample 420 having different angles of incidence, where each detector pixel in detector array 430 may be dedicated to a different optical path.

[0084] Although Figure 4A detector pixel 433 and detector pixel 437 are shown as a single detector pixel, each individually associated with an optical device, examples of the present disclosure may include multiple detector pixels associated with the same optical device and multiple optical devices associated with the same detector pixel.

[0085] In some examples, system 400 may integrate path lengths within a path length range and associate the integrated path lengths with detector pixels. By integrating path lengths, different azimuth angles may be resolved. Since there may be multiple sources for optical paths that may have the same azimuth angle (e.g., incident light from a single scattering event or incident light from multiple scattering events that change the path length), system 400 may resolve different sources. In some examples, resolving different azimuth angles may require a large - format (e.g., more than one hundred detector pixels) detector array.

[0086] In some examples, system 400 may be configured such that at least two first optical device / second optical device / detector pixel triads may resolve different angles of incidence. For example, as described above, light 454 may have an angle of incidence θ 1 , and light 455 may have an angle of incidence θ 3 . In some examples, the angle of incidence θ 1 may be different from the angle of incidence θ 3Differences. In some examples, for instance, light 454 may have an incident angle different from that of light 455, but may have the same path length. Those skilled in the art will understand that the same path length may include a tolerance that results in a 15% deviation. System 400 may associate different detector pixels or the same detector pixels in detector array 430 with different incident angles. For example, detector pixel 433 may be associated with incident angle θ 1 and detector pixel 437 may be associated with incident angle θ 3 In some examples, the optical system may operate at an infinite conjugate distance (i.e., an infinite distance at which the light rays are collimated), so the properties of the optical components (e.g., focal length, working distance, aperture, pitch, fill factor, tilt, and orientation) included in optical device unit 410 may be determined based on the incident angle.

[0087] In some examples, pore layer 486 may be located between optical device unit 410 and optical device unit 429. Pore layer 486 may be positioned one focal length away from optical device unit 410 and one focal length away from optical device unit 429. Additionally, system 400 may be configured to have detector array 430 positioned one focal length away from optical device unit 429. This configuration may require at least four layers in the stack of system 400: optical device unit 410 on the first layer, pore layer 486 on the second layer, optical device unit 429 on the third layer, and detector array 430 on the fourth layer. However, a smaller number of layers may be desirable for systems with, for example, a thinner stack structure.

[0088] Figures 4D to 4H A cross-sectional view of an exemplary optical component included in a system according to an example of the present disclosure is shown, and the system is configured to resolve multiple optical paths in a sample. System 400 may include one or more pore layers located on the same layer as one or more optical components or parts in the system. As Figure 4D shown, pore layer 486 may be located on the same layer as optical device unit 410. In some examples, pore layer 486 may be located on the surface of optical device unit 410. Although this figure shows pore layer 486 as being located on the bottom surface of optical device unit 410 (i.e., the surface facing optical device unit 429), examples of the present disclosure may include pore layer 486 located on the top surface of optical device unit 410. In some examples, pore layer 486 may be located on the same layer as optical device unit 429, as Figure 4E shown. Examples of the present disclosure may also include pore layer 486 located on two layers, which are: the same layer as optical device unit 410 and the same layer as optical device unit 429, as Figure 4FAs shown. In some examples, the pore layer may at least partially include opaque elements, such as metals. In some examples, the pore layer may be a lithographically patterned layer applied to one or more surfaces of the optical device unit.

[0089] Figure 4G One or more optical devices integrated into the structure of system 400 are shown. The integrated optical device may be configured to selectively transmit light through the optical device based on one or more properties such as the path length or the angle of incidence of the incident light. In some examples, system 400 may include one or more integrated optical devices included in optical device unit 429, as Figure 4H shown. In some examples, Figures 4G to 4H the integrated optical device shown in may be continuous with the surfaces of optical device unit 410 and optical device unit 429.

[0090] Although Figures 4D to 4H optical device 416 located on the same (e.g., integrated with) layer as optical device unit 429 is shown, examples of the present disclosure may include optical device 416 located on the same (e.g., integrated with) layer as optical device unit 410. Additionally, although Figures 4D to 4F pore layer 486 located on the bottom side of optical device unit 410 or the top side of optical device unit 429 is shown, examples of the present disclosure may include the same or additional pore layers located on the other side.

[0091] Figure 4I A cross-sectional view of a portion of an exemplary system according to an example of the present disclosure is shown. The system is configured to resolve multiple angles of incidence on a sample surface and reduce or eliminate light captured by TIR from a light source. System 400 may be configured such that output coupler 409 is in contact with the bottom surface (i.e., the flat surface) of optical device unit 429. System 400 may also be configured such that detector array 430 is located below substrate 442 (i.e., opposite optical device unit 429). By placing the top surface of output coupler 409 (i.e., the surface from which light exits output coupler 409) in contact with the bottom surface of optical device unit 429 and positioning detector array 430 below substrate 442 (i.e., in the direction away from the light exiting output coupler 409), detector array 430 can be prevented from erroneously detecting TIR-captured light that has directly exited output coupler 409. Additionally, positioning detector array 430 below substrate 442 can prevent light reflected from the bottom surface (i.e., the flat surface) of optical device unit 429 from being detected by detector array 430 and erroneously altering the measured signal.

[0092] Figure 5A cross-sectional view of a portion of an exemplary system in accordance with an example of the present disclosure is shown, the system being configured to resolve multiple angles of incidence on a sample surface using a single-layer optical device. System 500 may include one or more components as discussed in the context of Figures 4A to 4I and shown in these figures. Additionally, system 500 may include an optical device unit 512 that is capable of combining the functions of the optical device unit 410 and the optical device unit 429 shown in Figures 4A to 4I . The optical device unit 512 may include one or more optical devices, micro-optical devices, microlenses, or combinations of optical devices configured to collect incident light, adjust the beam size and shape, and focus the incident light. The optical device unit 512 may collect light 554 and light 555 incident on system 500 at angles of incidence θ 1 and angle of incidence θ 3 , respectively. The optical devices included in the optical device unit 512 may change the angle of the light (e.g., light 554 and light 555) (i.e., redirect the beam) such that the light is directed towards the detector array 530. Steering the light 554 and light 555 may result in angles of incidence on the detector array 530 that are less than the angles of incidence θ 1 and θ 3 , respectively. In some examples, the medium between the optical device unit 512 and the detector array 530 may be configured to have a refractive index such that the change in the angle (i.e., bending) of the light 554 and light 555 is increased. In some examples, the medium may be multifunctional and may include a conformal insulating material that provides mechanical support. In some examples, the optical devices included in the optical device unit 510 may preferentially collect the light rays included in the light 554 and the light rays included in the light 555, where the angle of incidence is within the range of the collection angle. In some examples, the range of the collection angle for the optical device coupled to the light 554 may be different from the range of the collection angle for the optical device coupled to the light 555.

[0093] Additionally, the optical devices 518 and 519 included in the optical device unit 512 may focus the light 554 and light 555 towards the detector pixels 533 and detector pixels 537 included in the detector array 530, respectively. Although systems with a two-layer optical device (e.g., as shown in Figures 4A to 4IThe system 400 shown may include an optical device unit (e.g., optical device unit 410) that may be configured to collect light, rotate the speed of light, and focus incident light. However, the optical device unit 512 may be configured to have a higher focusing ability (i.e., the degree to which the optical device converges or diverges incident light) than a system with a bilayer optical device. In some examples, the optical device unit 512 may include a plurality of silicon lenses or lenses including silica. In some examples, at least two optical devices included in the optical device unit 512 may have different geometric properties. A detailed discussion of the properties of the optical devices in the optical device unit 512 is provided below.

[0094] The system 500 may also include a pore layer 586. The pore layer 586 may include a plurality of openings configured to respectively allow light 554 and light 555 (e.g., any light with an incident angle within the collection angle range) to transmit through. In some examples, the pore layer 586 may be located on the outer surface (e.g., the housing) of the system 500 and may be configured to allow light to enter the system 500. Although Figure 5 the pore layer 586 is shown located on the outer surface of the system 500, examples of the present disclosure may include a pore layer 586 located on the other side (e.g., the inner surface of the system 500) or on another layer.

[0095] Each optical device included in the optical device unit 512 may be coupled to a detector pixel (e.g., detector pixel 533 or detector pixel 537) included in the detector array 530. Each optical device-detector pixel pair may be associated with an optical path in the sample 520. In some examples, the association may be an association between one optical device-detector pixel pair and one optical path. For example, the optical device 517 and the detector pixel 533 may form an optical device-detector pixel pair associated with the optical path from the light 554, and the optical device 518 and the detector pixel 537 may form another optical device-detector pixel pair associated with the optical path from the light 555. Although Figure 5 the detector pixels 533 and 537 are shown as single detector pixels, each individually associated with an optical device, examples of the present disclosure may include multiple detector pixels associated with the same optical device and multiple optical devices associated with the same detector pixel.

[0096] In some examples, the system can be configured to have a single-layer optical device to reduce the stack structure or height of the system. In some examples, the system can be configured to have a double-layer optical device to obtain a higher angular resolution, a larger angular range of incident light, or both. In some examples, the system can be configured to have a different number of optical device layers for light emitted from a light source and light collected from a sample. For example, the system can be configured to have one layer of optical device for light emitted from the light source and two layers of optical device for light reflected from the sample, or the system can be configured to have two layers of optical device for light emitted from the light source and one layer of optical device for light reflected from the sample.

[0097] Figure 6 A cross-sectional view of a portion of an exemplary system in accordance with an example of the present disclosure is shown, the system being configured to resolve the lengths of multiple optical paths using a double-layer optical device. System 600 can be proximate to, in contact with, resting on, or attached to sample 620. Sample 620 can include one or more locations, such as location 657 and location 659. System 600 can be configured to re-image and / or resolve optical paths in sample 620. For example, system 600 can be configured to re-image the path length of an optical path to another plane (e.g., a plane positioned closer to detector array 630). One or more layers of optical devices can be used to perform the re-imaging of the optical path. For example, system 600 can include a double-layer optical device and a detector array 630 positioned below (i.e., opposite the surface of sample 620) together with multiple layers supported by support 614. Located between the double-layer optical devices can be air, a vacuum, or any medium having a refractive index that contrasts with the refractive index of the optical devices.

[0098] System 600 can include a light source 602. The light source can be configured to emit light 650. Light source 602 can be any source capable of generating light, including but not limited to lamps, lasers, LEDs, OLEDs, EL sources, superluminescent diodes, supercontinuum sources, fiber-based sources, or a combination of one or more of these sources. In some examples, light source 602 can be capable of emitting light of a single wavelength. In some examples, light source 602 can be capable of emitting light of multiple wavelengths. In some examples, light source 602 can be a tunable source capable of generating SWIR features. In some examples, at least one of light sources 602 can include III-V materials, such as InP or GaSb.

[0099] Light from the light source 602 can be combined and amplified using the integrated tuning element 604, optical traces (not shown), and a multiplexer (not shown). In some examples, the integrated tuning element 604, optical traces, and multiplexer can be disposed on a substrate or included in a single optical platform such as a silicon photonics chip. The system 600 can also include a thermal management unit 601 for controlling, heating, or cooling the temperature of the light source 602. An output coupler 609 can be coupled to the multiplexer. The output coupler 609 can be configured to focus and / or condition (e.g., shape) the light 650 from the multiplexer toward the optical device 616. In some examples, the output coupler 609 can be configured as a single-mode waveguide that directs a well-defined (i.e., directional and sharp) light beam toward the optical device 616. In some examples, the light 650 from the output coupler 609 can be a light beam having any suitable shape (e.g., conical, cylindrical, etc.). The optical device 616 can collect the light 650 and collimate and / or tilt the light beam toward one or more locations in the sample 620. In some examples, the optical device 616 can include a flat bottom surface (i.e., the surface facing the output coupler 609) and a convex top surface (i.e., the surface facing away from the output coupler 609). Those skilled in the art will appreciate that the flat surface can include tolerances that result in a 15% deviation. The light emitted from the light source 602, collimated by the output coupler 609, transmitted through the optical device 616, and then exiting the system 600 can be referred to as light 652.

[0100] Light 652 can be directed at sample 620 and can be incident on location 657. A portion of light 652, referred to as light 654, can be reflected back toward system 600. Additionally, a portion of light 652 can be incident on location 659 and can be reflected back toward system 600 and can be referred to as light 655. Although the light 652 exiting system 600 can be a collimated beam, scattering events can occur along the optical paths directed to location 657 and location 659, which can cause light 654 and light 655 to become scattered beams. Both light 654 and light 655 can enter system 600 and can be incident on optical devices 618 and optical devices 619 included in optical device unit 610, respectively. Optical device unit 610 can include one or more optical devices to micro- / or focus incident light. For example, optical device 618 can collect light 654, and optical device 619 can collect light 655. Optical device 618 can change the angle of light 654 (i.e., redirect its beam) such that light 654 is directed toward optical device 623 included in optical device unit 629 (i.e., closer to normal incidence than the angle of incidence). In some examples, the medium between optical device unit 610 and optical device unit 629 can be configured to have a refractive index such that the change in the angle of light 654 (i.e., bending) is increased. In some examples, the medium can be multifunctional and can include a conformal insulating material that provides mechanical support. Similarly, optical device 619 can change the angle of light 655 such that light 655 is directed toward optical device 627 included in optical device unit 629. In some examples, optical device 618, optical device 619, or both can be configured to focus incident light (e.g., light 654 and light 655). In some examples, optical device unit 610 can preferentially collect light rays included in light 654, light 655, or both, where the angle of incidence is within the range of the collection angle. In some examples, optical device unit 610 can include multiple silicon lenses or lenses including silica. Although Figure 6 Optical device unit 610 attached to support 614 is shown, but examples of the present disclosure can include optical device unit 610 attached to or coupled to optical device unit 629 by mechanical features etched into optical device unit 610, optical device unit 629, or both. In some examples, at least two optical devices included in optical device unit 610 can have different geometric properties. A detailed discussion of the properties of the optical devices in optical device unit 610 is provided below.

[0101] System 600 may include a pore layer 686. The pore layer 686 may include openings 687 and 689 configured to allow light 654 and light 655 (e.g., any light having an incident angle within the collection angle range) to transmit therethrough, respectively. The light 654 that has transmitted through the opening 687 may be directed to an optical device 623 included in the optical device unit 629. Similarly, the light 655 that has transmitted through the opening 689 may be directed to an optical device 627 included in the optical device unit 629. The optical device unit 629 may include a plurality of optical devices attached to a substrate, such as the optical device 623 and the optical device 627. In some examples, the optical device 623 and the optical device 627 may be any type of optical device and may include any type of material conventionally used in optical devices. In some examples, two or more of the optical devices in the optical device unit 629 may have the same optical and / or geometric properties. Those skilled in the art will understand that the same optical properties and geometric properties may include tolerances that result in a 15% deviation.

[0102] The light 645 may undergo some refraction from the optical device 618. The optical device 623 may re - collimate the light 654 and / or focus the light 654 onto a detector pixel 633 included in the detector array 630. Similarly, the optical device 627 may re - collimate the light 655 and / or focus the light 655 onto a detector pixel 637 included in the detector array 630. In some examples, the system 600 may be configured such that the light 654 is redirected by the optical device unit 610 and focused by the optical device unit 629. In some examples, the system 600 may be configured such that the light 654 is redirected by both the optical device unit 610 and the optical device unit 629. In some examples, the optical device unit 629 may include a plurality of silicon lenses or lenses including silica. Although Figure 6 the optical device unit 629 is shown attached to the support 614, examples of the present disclosure may include an optical device unit 629 attached to or coupled to the optical device unit 610 by mechanical features etched into the optical device unit 629, the optical device unit 610, or both. In some examples, at least two of the optical devices included in the optical device unit 629 may have different geometric properties. A detailed discussion of the properties of the optical devices in the optical device unit 629 is provided below.

[0103] Light 654 can be transmitted through the optical device 623 and detected by the detector pixels 633 included in the detector array 630. The detector array 630 can include one or more detector pixels, such as detector pixel 633 and detector pixel 637 disposed on a substrate. In some examples, the substrate can be a silicon substrate. In some examples, at least one detector pixel can be controlled independently from other detector pixels in the detector array 630. In some examples, at least one detector pixel is capable of detecting light in the SWIR range. In some examples, at least one detector pixel can be a SWIR detector capable of operating between 1.5 μm - 2.5 μm. In some examples, at least one detector pixel can be a detector based on HgCdTe, InSb, or InGaAs. In some examples, at least one detector pixel is capable of detecting the incident position and / or angle.

[0104] In addition, light 655 can be transmitted through the optical device 627 and detected by the detector pixel 637. The detector pixel 633 and the detector pixel 637 can be coupled to an integrated circuit, such as ROIC 641. In some examples, the detector pixel 633 and the detector pixel 637 can be coupled to the same circuit. In some examples, the detector pixel 633 and the detector pixel 637 can be coupled to different circuits. Each circuit in the ROIC 641 can store the charge corresponding to the light (or photons of light) detected on the corresponding detector pixel that will be sampled and read out by a processor or a controller in the integration capacitor. The stored charge can correspond to one or more optical properties of the detected light (e.g., absorbance, transmittance, and reflectance).

[0105] The system 600 can include a plurality of optical devices (e.g., optical device 618 and optical device 619) included in the optical device unit 610 and a plurality of optical devices (e.g., optical device 623 and optical device 627) included in the optical device unit 629, wherein each of the optical devices can be coupled to a detector pixel (e.g., detector pixel 633 or detector pixel 637) included in the detector array 630. Each first optical device / second optical device / detector pixel triad can be associated with an optical path in the sample. In some examples, the association can be an association between one first optical device / second optical device / detector pixel triad and one optical path. For example, the optical device 618, the optical device 623, and the detector pixel 633 can be associated with the optical path from the light 654. The optical device 619, the optical device 627, and the detector pixel 637 can be associated with the optical path from the light 655. In this way, the system 600 is capable of re - imaging and resolving multiple optical paths with different path lengths in the sample 620, where each detector pixel in the detector array 630 can be associated with a different optical path. Although Figure 6Detector pixel 633 and detector pixel 637 are shown as a single detector pixel, each individually associated with an optical device, but examples of the present disclosure may include multiple detector pixels associated with the same optical device and multiple optical devices associated with the same detector pixel.

[0106] As shown, system 600 may be configured such that at least two first optical device / second optical device / detector pixel elements may resolve different path lengths. For example, light 654 may have a first optical path length, and light 655 may have a second optical path length. Due to different depths at different positions where the light rays reflect away (e.g., position 657 and position 659), the first optical path length associated with light 654 may be different from the second optical path length associated with light 655. In some examples, light 654 may have the same angle of incidence as light 655, but may have a different path length. Those skilled in the art will understand that the same angle of incidence may include a tolerance that results in a 15% deviation. System 600 may couple different detector pixels in detector array 630 to different path lengths. For example, detector pixel 633 may be associated with the first optical path length, and detector pixel 637 may be associated with the second optical path length. In some examples, the optical system may operate at a finite yoke distance (i.e., a finite distance at which the light rays are collimated), and the properties of the optical devices included in optical device unit 610 (e.g., focal length, working distance, aperture, pitch, fill factor, tilt, and orientation) may be determined based on the range of collection angles. In some examples, at least two optical devices included in optical device unit 610 may have the same geometric properties, but may be located in different regions of optical device unit 610. A detailed discussion of the properties of the optical devices in optical device unit 610 is provided below.

[0107] In some examples, the shape, size, and geometric properties of the optical devices included in optical device unit 610 may be different for an optical system configured to resolve different angles of incidence (e.g., Figures 4A to 4I system 400 shown in Figure 5 or system 500 shown in Figure 6 compared to an optical system configured to resolve different path lengths (e.g.,

[0108] In some examples, each first optical device / second optical device / detector pixel triad may be associated with a range of collection angles. As shown, light 654 may be scattered from a location 657 that has a shape similar to a cone, for example. System 600 may azimuthally integrate the angles of the rays included in light 654. Since the path lengths of the rays may be the same, integration of the angles within the collection angle range may reduce the number of angular bins, the number of detector pixels, and the complexity of the optical devices required for the optical system. Those skilled in the art will understand that the same path length may include tolerances that result in a 15% deviation. For example, an optical system that does not integrate angles may require at least eight detector pixels, while an optical system that integrates angles may require a smaller number of detector pixels.

[0109] In addition to requiring a smaller number of detector pixels, system 600 may utilize a detector array in a smaller format (i.e., less than one hundred pixels), which may have better performance (e.g., optical efficiency, fill factor, and / or reliability) than a larger format detector array. Additionally, by integrating the angles of the rays, system 600 inherently performs spatial averaging of the nominal equivalent optical path incident on the detector pixels. Spatial averaging of the nominal equivalent optical path may result in more light being incident on the detector pixels, which may produce a higher signal-to-noise ratio (SNR). Since unimportant rays may be "cancelled" or averaged out, spatial averaging may also result in better measurement accuracy.

[0110] Although the pore layer 686 is shown Figure 6 as being located between optical device unit 610 and optical device unit 629, embodiments of the present disclosure may include a pore layer 686 that is located on the same layer as one or more optical devices or components in the system. Similar to Figures 4D to 4IIn the embodiments shown, system 600 may be configured to have a pore layer 686 located on the surface of the optical device unit 610. In some examples, the pore layer 686 may be located on the same layer (e.g., surface) as the optical device unit 629. In some examples, the pore layer 686 may be located on the same layer as the optical device unit 610 and on the same layer as the optical device unit 629. In some examples, system 600 may include one or more recessed optical devices in the optical device unit 610. The recessed optical devices may be configured to selectively transmit light through the optical device based on one or more attributes such as the path length and / or the angle of incidence of the incident light. In some examples, system 600 may include one or more recessed optical devices in the optical device unit 629. One or more of the recessed optical devices may be continuous with the surfaces of the optical device unit 610 and the optical device unit 629. In some examples, system 600 may include one or more etched holes or drilled holes for selectively transmitting light through the bilayer optical device to the detector array 630. Using one or more etched holes or drilled holes that serve as the pore layer, system 600 may include one or more spacers located between the surfaces of the bilayer optical device. One or more spacers may be used to mechanically support the optical device.

[0111] Figure 7 A cross-sectional view of a portion of an exemplary system according to an example of the present disclosure is shown, the system being configured to resolve the lengths of multiple optical paths using a single-layer optical device. System 700 may include one or more components as discussed and shown in the context of Figure 6 and as shown in the figures. Additionally, system 700 may include an optical device unit 712 that is capable of incorporating Figure 6Functions of the optical device units 610 and 629 shown. The optical device unit 712 may include one or more optical devices, micro-optical devices, microlenses, or combinations thereof configured to collect incident light, adjust the beam size and shape, and focus the incident light. The optical device 718 included in the optical device unit 712 may collect the light 754 reflected from the position 757. The optical device 719 included in the optical device unit 712 may collect the light 755 reflected from the position 759. The optical devices (e.g., the optical device 718 and the optical device 719) included in the optical device unit 712 may change the angle of the light (e.g., the light 754 and the light 755) (i.e., redirect the light beam) such that the light is directed towards the detector array 730. In some examples, the incident angles of the light 754 and the light 755 may be the same, and the optical device 718 and the optical device 719 may be configured to redirect the incident light to the same extent. Those skilled in the art will understand that the same incident angle and the same extent may include tolerances that result in a 15% deviation. In some examples, the medium between the optical device unit 712 and the detector array 730 may be configured to have a refractive index such that the change in the angle (i.e., bending) of the light 754 and the light 755 is increased. In some examples, the medium may be multifunctional and may include a conformal insulating material that provides mechanical support. In some examples, the optical device unit 712 may preferentially collect the light rays included in the light 754 and the light rays included in the light 755, where the incident angle is within the range of the collection angle.

[0112] In addition, the optical device 718 and the optical device 719 included in the optical device unit 712 may focus the light 754 and the light 755 towards the detector pixel 733 and the detector pixel 737 included in the detector array 730, respectively. Although a system with a bilayer optical device (e.g., the system 600 shown as Figure 6 shown) may include an optical device unit (e.g., the optical device unit 610) configured to collect light, rotate the light beam, and focus the incident light, the optical device unit 712 may be configured to have a higher focusing ability (i.e., the degree to which the optical device converges or diverges the incident light) than a system with a bilayer optical device. In some examples, the optical device unit 712 may include multiple silicon optical devices.

[0113] The system 700 may further include a pore layer 786. The pore layer 786 may include a plurality of openings configured to respectively allow the light 754 and the light 755 (e.g., any light with an incident angle within the range of the collection angle) to transmit through. In some examples, the pore layer 786 may be located on the outer surface (e.g., the housing) of the system 700 and may be configured to allow light to enter the system 700. Although Figure 7The pore layer 786 is shown on the outer surface of the system 700, but examples of the present disclosure may include a pore layer 786 on the other side (e.g., the inner surface of the system 700) or on another layer.

[0114] Each optical device included in the optical device unit 712 may be coupled to a detector pixel (e.g., detector pixel 733 or detector pixel 737) included in the detector array 730. Each optical device-detector pixel pair may be associated with an optical path in the sample 720. In some examples, the association may be an association between one optical device-detector pixel pair and one optical path. For example, the optical device 718 and the detector pixel 733 may form an optical device-detector pixel pair associated with the light 754 (or light having the same optical path length as the light 754), and the optical device 719 and the detector pixel 737 may form another optical device-detector pixel pair associated with the light 755 (or light having the same optical path length as the light 755). Those skilled in the art will understand that the same optical path length may include a tolerance that results in a 15% deviation. Although Figure 7 The detector pixel 733 and the detector pixel 737 are shown as a single detector pixel, each individually associated with an optical device, but examples of the present disclosure may include multiple detector pixels associated with the same optical device and multiple optical devices associated with the same detector pixel.

[0115] In some examples, the system may be configured to have a single layer of optical devices to reduce the stacked structure or height of the system. In some examples, the system may be configured to have a double layer of optical devices to obtain a higher angular resolution, a larger angular range of incident light, or both. In some examples, the system may be configured to have a different number of optical device layers for light emitted from the light source and light collected from the sample. For example, the system may be configured to have one layer of optical devices for light emitted from the light source and two layers of optical devices for light collected from the sample, or the system may be configured to have two layers of optical devices for light emitted from the light source and one layer of optical devices for light collected from the sample.

[0116] Although Figures 2 to 7 A system close to the sample is shown, but embodiments of the present disclosure may include a system configured to contact the surface of the sample. In some examples, the surface of the optical device unit (e.g., optical device unit 410, optical device unit 512, optical device unit 610, or optical device unit 712) may contact the surface of the sample. Generally, a closer proximity of the sample to the optical device unit may result in fewer and smaller optical components in the system, better measurement accuracy, and lower power consumption of the system.

[0117] The close proximity of the device can utilize a reduced effective numerical aperture (NA) of the light leaving the sample. The reduced effective NA can be used to characterize the angular range that the system can accept as reflected light from the sample. Due to Snell's law, this reduced effective NA can be attributed to the angle of incidence on the optical device and the detector that is closer to normal incidence. As the angle of incidence gets closer to normal, the aperture size and spacing of the optical device can become smaller, resulting in a smaller system. Additionally, the detector can receive a higher light power, which can result in better measurement accuracy and a system that can be configured for lower power consumption.

[0118] Figure 8 Snell's law according to an example of the present disclosure is shown. Snell's law can describe the properties of light rays refracted at the interface between two materials with different refractive indices. Snell's law is expressed as:

[0119] n 1 sinθ 1 =n 2 sinθ 2 (1)

[0120] Material 810 can have a refractive index of n 1 , and material 812 can have a refractive index of n 2 , where the refractive index n 1 can be different from the refractive index n 2 . The light ray can be incident on the interface between material 810 and material 812 at an angle of incidence θ 1 . Due to the difference in refractive indices between the two materials, the light ray can be refracted and can enter material 812 at a refraction angle θ 1 that is different from the angle of incidence θ 2 . If the refractive index of material 810 is less than the refractive index of material 812, the refraction angle θ 2 can be reduced (i.e., closer to normal incidence).

[0121] With a high enough light power, the optical device unit can act as an immersion objective. An immersion objective can be a system in which the optical device and the sample are surrounded or immersed in a medium with a contrasting refractive index. The contrasting refractive index can result in a greater change in the reduced effective NA compared to a non-immersion (e.g., the optical device and the sample are surrounded by air) system. The greater change in the reduced effective NA can result in more light refraction, which can reduce optical aberration and can result in better measurement accuracy. Optical immersion can also eliminate or reduce TIR at the external interface of the system (e.g., the interface where the system contacts the sample), which can result in more light reaching the detector. Since more light reaches the detector, the light source included in the system can be driven with less power, and thus the system may require less power.

[0122] In addition, the close proximity of the optical device unit to the sample may allow the system to use a well-defined (i.e., distinct and differentiable) interface such as the external interface of the system (e.g., the interface where the system contacts the sample) as a reference. The system may need to accurately reference the "start" or "edge" of the sample in order to re-image and resolve multiple optical paths within the sample. When the external interface of the system (e.g., the interface where the system contacts the sample) is used as a reference, fewer optical elements or components (e.g., a separate window) may be required because additional optical components may otherwise be needed to form a well-defined interface. Fewer optical components can result in a more compact system.

[0123] In addition to positioning the device close to (e.g., touching) the sample, the measurement area of the sample can affect the system's ability to accurately re-image and resolve multiple optical paths within the sample. One factor that can affect accurate re-imaging and resolution can be the measurement path length. The measurement path length can be selected based on a target (e.g., pre-determined) path length, which can be the path length such that the spectral signal measured by the detector accurately represents one or more desired attributes of the sample. The target measurement path length can be determined based on the scale length of the sample. The scale length of the sample can be based on the average absorption length in the sample and the reduced scattering length in the sample.

[0124] The average absorption length in the sample can be the distance over which light can attenuate. If the measurement path length is greater than the average absorption length, the remaining signal (i.e., the signal that has not yet scattered) or the measured signal intensity can be reduced, while any noise sources may not attenuate an equal amount. Due to the imbalance in attenuation, the SNR can be lower. The average absorption length can be defined by the Beer-Lambert law, which can mathematically describe the absorbance A of a substance in a sample at a given wavelength:

[0125] A = ecL (2)

[0126] where e is the molar absorptivity (which can vary with wavelength), L is the path length that the light needs to travel through the sample, and c is the concentration of the substance of interest.

[0127] If the background absorbance (i.e., the absorbance of substances different from the substance of interest) is high, the path length that the light needs to travel through the sample can be less than the average absorption length. If the background absorbance is negligible, the path length can be the same as the average absorption length. Those skilled in the art will understand that the same path length can include a tolerance that results in a 15% deviation. In some examples, the average absorption length can be selected such that the average absorption length is greater than or equal to the path length that the light needs to travel through the sample.

[0128] The reduced scattering length can be the distance over which information about the optical path is lost (i.e., random or uncorrelated). The reduced scattering length can be determined by the following formula:

[0129] μ s ' = μ s (1 - g)(3)

[0130] where 1 / μ s is the mean free path between scattering events, and g is the scattering anisotropy. If the measured path length is greater than the reduced scattering length, the measurement accuracy can be affected. In some examples, the measured path length can be selected such that the measured path length is less than the reduced scattering length.

[0131] In some examples, the mean absorption length can be different from the reduced scattering length, and the measured path length can be selected based on the smaller of the mean absorption length and the reduced scattering length. In some examples, the mean absorption length can be short, or the absorbance of light in the sample can be strong, such that the signal of the reflected light is not detected, and the system can be configured to increase the optical power of the light source or increase the sensitivity of the detector for compensation. In some examples, the amount of this compensation can be based on any combination of power consumption, optical damage to the sample, unwanted thermal effects in the sample, effects on photon shot noise, stray light that has not transmitted through the sample that is detected, or effects. Thus, the selection of the measured path length can affect not only the measurement accuracy but also the power consumption, reliability, and lifetime of the system.

[0132] In addition or alternatively, for example, the system can be configured to utilize an effective scale length when the optical parameters of the sample vary with wavelength (e.g., by more than 10%). The effective scale length can be determined by calculating the individual scale lengths for each wavelength and averaging the individual scale lengths over the wavelength range of interest. In some examples, the individual scale lengths for each wavelength can be calculated to determine the range of the individual scale lengths. The system can be configured to select the minimum scale length (within the range of the individual scale lengths), the maximum scale length (within the range of the individual scale lengths), or any scale length between the minimum scale length and the maximum scale length. In some examples, the measured path length can be selected based on the mean absorption length, the reduced scattering length, the minimum scale length, the maximum scale length, or any combination.

[0133] As described above, the scale length can be used to determine the size of the measurement region on the sample. The light outside the measurement region can be light that has undergone multiple random scattering events within the sample, and thus, this light can be uncorrelated with the optical path traveling within the sample. Uncorrelated light may not provide useful information for accurate measurement and can therefore be discarded or ignored without sacrificing accurate measurement.

[0134] For example, the wavelength of interest can be between 1500 nm and 2500 nm (i.e., the SWIR range), and the average absorption length and reduced scattering length averaged over the wavelength of interest can be 1 mm, which can correspond to a scale length of 1 mm. This scale length can correspond to a sample area for collecting light leaving the sample with a diameter of 1 to 2 mm. That is, most (e.g., greater than 70%) of the optical power leaving the sample can be concentrated within the area with a diameter of 1 to 2 mm, and the light rays leaving the sample outside this area can be ignored.

[0135] The scale length can also be used to determine the size of the input beam emitted from the output coupler. The size of the beam can affect the optical power (i.e., optical intensity) and diffraction effects. Measurement accuracy can be beneficial for collimating the input beam so that the system operates with sufficient optical power (e.g., a signal with a sufficiently high SNR that can be detected by the detector) and minimal diffraction effects. For example, a scale length of 1 mm can correspond to a collimated input beam with a beam diameter between 100 μm and 300 μm. In some examples, the input beam can be configured to have a beam diameter of less than 175 μm.

[0136] Similar to the properties of the input beam, the properties of the optical device unit can also affect the system. The optical device unit can be formed on a single substrate or layer, or can be formed on two or more substrates or layers. In some examples, the optical device unit, detector array, light source, or any combination can be mounted on the same optical platform. In some examples, the optical device unit can have a flat (i.e., planar) surface that contacts the sample. Configuring the optical device with a flat surface can reduce wafer processing and manufacturing complexity. In some examples, another surface (i.e., the surface opposite the sample) can be convex to enhance optical power. In some examples, this another surface can be a single convex refractive surface. In some examples, the thickness of the optical device unit can be based on the amount of light bending. In some examples, the thickness can be between 100 μm and 300 μm.

[0137] Figures 9A to 9B A top view and a perspective view of an exemplary optical device unit according to an example of the present disclosure are shown. Group 900 can include a plurality of units, each unit including at least three regions: emission region 916, reference region 922, and measurement region 929.

[0138] Emission region 916 can be configured to prevent any specular reflection from reaching the detector array. Emission region 916 can include a light blocker or light absorber capable of blocking or absorbing light. In some examples, the light blocker can include any material that prevents incident light from reflecting (e.g., an anti-reflection coating). In some examples, the light blocker can include any material that reflects at a wavelength different from the detection wavelength of the detector array. In some examples, the emission region can include an opaque mask.

[0139] The reference region 922 may include any type of optical device (e.g., negative microlens) configured to diffuse an incident light beam. Light emitted from the light source may be directed to a reference (e.g., reference 222 included in system 200), which may relay the light to the reference region 922. The reference region 922 may diffuse the light such that one or more light beams are directed to detector pixels on the detector array. In some examples, the reference region 922 may include a negative lens or a lens with a negative focal length. In some examples, the reference region 922 may include a prism. In some examples, the reference region 922 may include a different prism wedge for each detector pixel in the detector array. In some examples, the reference region 922 may include a beam splitter. In some examples, the reference region 922 may be configured to diffuse or split the light into multiple light beams. In some examples, the reference region 922 may be configured to uniformly diffuse the light such that one or more properties of each light beam are the same. Those skilled in the art will understand that the same properties may include tolerances that result in a 15% deviation. In some examples, the reference region 922 may be configured to diffuse the light beams such that the intensities of at least two light beams are different. In some examples, the reference region 922 may include multiple optical devices. In some examples, the size and / or shape of the optical devices included in the reference region 922 may be based on the number of detector pixels and / or the properties of one or more light beams leaving the reference region 922. In some examples, one or more pore layers may be located in the reference region 922 to control the properties and / or direction of the light leaving the reference region 922.

[0140] The measurement region 929 may include one or more collection optical devices (e.g., positive microlenses). The collection optical devices may be configured to re-image and resolve multiple optical paths in the sample, as described above. The system may be configured to switch or alternate between emitting light from the light source to be incident on the reference region 922 and emitting light from the light source to be incident on the measurement region 929. The properties of the collection optical devices will be discussed below.

[0141] Although Figures 4A to 7 illustrates a system including units where each unit may include one light beam leaving the sample from the output coupler and collected by the conjugate optical system and the detector array, embodiments of the present disclosure include systems having multiple units. Figure 9CA top view of an exemplary optical device unit and a detector array included in a plurality of groups in a system according to an embodiment of the present disclosure is shown. The system may include a plurality of groups 900 coupled to a detector array 930. In some examples, one or more optical devices included in a measurement region 929 may be "shared" between adjacent groups 900. In some examples, the system may be configured with one or more groups having light sources that alternately emit light to the shared optical device. In some examples, the system may be configured with 27 groups 900 and a 9×3 detector array 930. In some examples, each group 900 may be spaced apart from another group 900 by at least 2 mm. Although Figures 9A to 9B A group 900 is shown with a reference region 922 disposed between an emission region 916 and a grid of 3×3 optical devices included in a measurement region 929, but examples of the present disclosure may include any arrangement of the three regions and any arrangement of the optical devices included in the measurement region 929. For example, the emission region 916 may be located in the center of the group 900, and the optical devices may surround the outer edge of the emission region 916.

[0142] As described above, the configuration and properties of the optical devices included in the optical device unit may be based on a variety of factors. These properties may include effective focal length, working distance, material of the optical device, fill factor, aperture size, pitch, tilt (or decentration), and orientation (or degree of rotation), as will be discussed.

[0143] Based on the relationship between the collection angle range and the position on the surface of the detector (or detector pixel) where the light is incident, the system may be configured to have an effective focal length. The system may also be based on the integrated configuration of the detector array.

[0144] Since the optical device unit is in the path between the sample and the detector, the material of the optical device may affect the optical properties of the detected light, thereby affecting the measurement accuracy. To allow the light leaving the sample to reach the detector array, the optical device may be configured with a material that is transparent in the wavelength range of interest so that light can be prevented from being reflected off the surface of the optical device. Additionally, in examples where the optical device unit is in contact with the sample, the material of the optical device may be based on the resistance of the material to degradation when the optical device is chemically and physically exposed to the sample. Furthermore, other considerations may be taken into account, such as compatibility with wafer-level processing for any pattern (e.g., etch profile) used to fabricate the optical device unit, availability and cost of the material.

[0145] The material of the optical device unit can also be selected based on the refractive index of the sample. For example, when the refractive index of the sample is 1.42 (or within 10%), the system can be configured to have an optical device unit (e.g., a unit of a silicon lens) with a refractive index of 3.4 (or within 10%). The incident angle of light at the external interface of the system (e.g., the interface where the system contacts the sample) can be 45°, so that a refraction angle of 16.9° can be generated. In this way, the material of the optical device unit can be selected such that the incident angle on the detector array surface can be closer to the normal, which can enable the detector to receive higher optical power, obtain better measurement accuracy, and a system that can be configured for lower power consumption.

[0146] In addition, the material of the optical device unit can be selected such that less "diffusion" of light occurs (i.e., the dispersion of the light beam between the external interface of the system (e.g., the interface where the system contacts the sample) and the surface of the detector). For example, light incident on the external interface of the system (e.g., the interface where the system contacts the sample) with an incident angle of 60° can obtain a refraction angle of 20.9°. In the case where there is no refractive index contrast between the optical device unit and the sample, the diffusion will be 15° (i.e., 60° - 45°), while in the case where there is a refractive index contrast between the optical device unit and the sample, the diffusion of the light can be 4° (i.e., 20.9° - 16.9°). The smaller diffusion of the light can result in a narrower range of collection angles, which can obtain a smaller optical device and a more compact system.

[0147] In some examples, the wavelength range of interest can be SWIR (i.e., 1500 nm - 2500 nm), and the optical device unit can include single-crystalline silicon, sapphire, fused silica, oxide glass, chalcogenide glass, gallium arsenide (GaAs), zinc selenide (ZnSe), germanium (Ge), or any combination of these materials.

[0148] The diameter of the optical device can be based on the size of the light beam emitted from the light source. For example, a system with a beam diameter configured between 100–300 μm can also configure the diameter of the optical device unit between 100–300 μm.

[0149] The fill factor of the optical device unit can represent the percentage or fraction of the light rays leaving the collected sample. Generally, the reduction in the diffusion of the incident light beam can lead to a larger fill factor at the optical device unit (i.e., the ratio of the area of the light directed to the detector to the total area of the optical device), and thus can lead to higher optical efficiency. The fill factor of the optical element can be determined by the following method:

[0150]

[0151] Where AD is the aperture size. The fill factor FF of the lens or microlens can represent the amount of light that exits the sample, refracts into the system, and then transmits through the aperture. In some examples, the aperture size of the aperture associated with the optical device included in the optical device unit can be based on the divergence of the incident light rays. When the divergence amount of the incident light rays is small, the aperture size and the optical device pitch can be reduced, so that a high fill factor can be achieved without losing the incident light rays including relevant information (for example, information that can contribute to obtaining better measurement accuracy). In some examples, the optical device unit can be configured with a fill factor FF of 25% or greater. In some examples, the optical device unit can be configured with a fill factor FF of 50% or greater. In some examples, the optical device unit can be configured with a fill factor FF of 60% or greater.

[0152] The pitch of the optical device unit can be the distance between adjacent optical devices and affects the size of the optical devices. In some examples, the pitch can be based on the fill factor of the optical device unit. As shown in Equation 4, the fill factor of the optical device unit can be related to the aperture size, so the pitch of the optical device unit can also be based on the aperture size. To increase the fill factor and the efficiency of capturing the light rays exiting the sample, the pitch can be greater than the aperture size. For example, for an aperture size between 100 μm and 300 μm, the optical devices can be configured to have a pitch between 125 μm and 500 μm. In some examples, the aperture size can be configured to be 175 μm in diameter, the pitch can be 250 μm, and the fill factor can be 38.4%.

[0153] In addition or alternatively, the optical device spacing and aperture size can be based on the range of collection angles. The aperture size can determine which of the light rays leaving the sample are accepted by the optical device (i.e., transmitted through the detector) and which are rejected (i.e., blocked from reaching the detector). The sample material and substances in the sample can result in high scattering anisotropy. As a result, the light collection efficiency (i.e., the efficiency of collecting scattered light) can be based on the range of collection angles. Although a wider collection angle can result in more light being collected (i.e., higher optical power), the collected light will include a larger proportion of unwanted light (e.g., noise or irrelevant light). The collected light rays at different angles can have different importance or relevance for accurate measurement. In some examples, when the light deviates from normal incidence on the detector surface (e.g., greater than 70°), the optical power of the light ray can be lower. The light rays with an incident angle deviating from normal incidence can include light rays with a smaller crossing angle with the light emitted by the light source (which can result in a larger uncertainty in the scattering position or path length) and light rays with a large number of scattering events. As a result, the light rays with an incident angle deviating from normal incidence may be less relevant and may result in less accurate measurement. In addition, the light rays deviating from normal incidence can include light scattered from positions near the surface of the sample. In some applications, the substances of interest in the sample can be located deep within the sample, so the light rays scattered from positions near the surface of the sample may not provide relevant information for the measurement.

[0154] Affected by the range of collection angles can be the aperture size, the optical or optical spacing, the collection efficiency, the optical power incident on the detector, and the power of the system. The range of collection angles that the system can be configured to measure can be based on a target (e.g., predetermined) range of collection angles. The target range of collection angles can be determined based on several factors, such as the collection efficiency, the geometric path uncertainty, the number of scattering events that may occur in the sample, the penetration depth, and the limitations of the optical design, which can be determined based on the path length of the light ray. To determine the path length of the light ray, multiple uncertainties present can be considered. The total path length uncertainty ΔPL can include the spatial resolution uncertainty Δspatial, the angular resolution uncertainty Δangular, the input Gaussian angular divergence Δinput, and the low-angle sample scattering uncertainty Δmultiple_scatter, and can be defined as:

[0155] ΔPL 2 =(Δspatial) 2 +(Δangular) 2 +(Δinput) 2 +(Δmultiple_scatter) 2 (5)

[0156] The properties of one or more optical devices and the pore layer in the system can be configured based on the spatial resolution uncertainty.Figure 10 An exemplary configuration of light rays with spatial resolution uncertainty according to an example of the present disclosure is shown. System 1000 may be in contact with or near sample 1020. Light may exit system 1000 at position 1006 and may travel through sample 1020 for a length d 11 , reaching position 1010. The angle of incidence of the light at position 1010 may be the angle of incidence θ 1 . A portion of the light may be scattered at a scattering angle θ 4 , travel through sample 1020 for a length d 12 , and may reach the outer interface of the system (e.g., the interface where the system contacts the sample) at position 1016. The distance between position 1006 and position 1016 may be referred to as distance x. Another portion of the light may further travel into sample 1020 for a total length d 21 , reaching position 1040. In some examples, the angle of incidence of the light at position 1040 may also be the angle of incidence θ 1 and the light may also be scattered at a scattering angle θ - 4 . The scattered light may travel through sample 1020 for a length d 22 , and may reach position 1046 at the outer interface of the system (e.g., the interface where the system contacts the sample). The spatial resolution or distance between position 1016 and position 1046 may be referred to as the spatial resolution or distance Δx.

[0157] The spatial resolution uncertainty Δspatial may be based on the difference in the optical path lengths between the scattered light incident at position 1016 and the scattered light incident at position 1046, and may be defined as:

[0158] Δspatial = d 21 + d 22 - d 11 - d 12 (6)

[0159] According to the sine law:

[0160]

[0161]

[0162]

[0163]

[0164]

[0165] Therefore, the spatial resolution uncertainty Δspatial can be reduced to:

[0166]

[0167] As shown in Equation 12, the spatial resolution uncertainty Δspatial can decrease with the angle of incidence θ 1 while the scattering angle θ 4 can increase. Additionally, the spatial resolution uncertainty Δspatial can increase with the spatial resolution Δx (i.e., the distance between the light incident at position 1016 and the light incident at position 1046). In some examples, the aperture size, tilt, or orientation of the optical device, or a combination thereof, can be configured based on the spatial resolution uncertainty Δspatial. In some examples, the spatial resolution uncertainty Δspatial can be between 150 μm - 200 μm and can be the same as the angle of incidence θ 1 = 45° and a collection angle of 45° (which can be equal to the scattering angle θ 4 ).

[0168] The properties of one or more optical devices in the system can also be configured based on the spatial resolution uncertainty. Figure 11 An exemplary configuration of rays with angular resolution uncertainty according to an example of the present disclosure is shown. System 1100 can be in contact with or near sample 1120. Light can leave system 1100 at position 1106 and can travel through sample 1120 for a length d 11 , reaching position 1110. The angle of incidence at position 1110 can be the angle of incidence θ 1 . A portion of the light can be scattered from position 1110 at a scattering angle θ 5 , travel through sample 920 for a length d 12 , and can reach position 1146 at the outer interface of the system (e.g., the interface where the system contacts the sample). A change in the refractive index at the outer interface of the system (e.g., the interface where the system contacts the sample) can result in a refraction angle θ 8 . Another portion of the light can further travel into sample 1120, travel a total length d 21 , and reach position 1140. In some examples, the angle of incidence of the light at position 1140 can also be the angle of incidence θ 1 and the light scattered from position 1140 can also have a scattering angle θ 6 . In some examples, the scattering angle θ 6 can be different from the scattering angle θ 1 . The light scattered from position 1140 can travel through sample 1120 for a length d 22 , and can reach position 1146 at the outer interface of the system (e.g., the interface where the system contacts the sample). A change in the refractive index at the outer interface of the system (e.g., the interface where the system contacts the sample) can result in a refraction angle θ7 The distance between position 1106 and position 1146 can be referred to as distance x. In some examples, the refraction angle θ 8 can be different from the refraction angle θ 7 by an angular resolution Δθ.

[0169] The uncertainty of the angular resolution Δangular can be based on the difference in the refraction angles between two scattered light beams (e.g., the light scattered from position 1110 and the light scattered from position 1140), and can be defined as:

[0170] Δangular = d 21 + d 22 - d 11 - d 12 (13)

[0171] According to the sine law and Snell's law:

[0172]

[0173]

[0174]

[0175]

[0176] Therefore, the angular resolution uncertainty Δangular can be reduced to:

[0177]

[0178] As shown in Equation 18, the angular resolution uncertainty Δangular increases as the distance x between the light emitted from the light source and the exit position increases. In some examples, the system can be configured to have a distance between the light source based on the angular resolution uncertainty Δangular and the corresponding optical device included in the optical device unit. In some examples, the system can be configured to have a collection angle range (i.e., an angular interval) based on the angular resolution uncertainty Δangular. In some examples, the tilt, orientation, or both of the optical device can be configured based on the spatial resolution uncertainty Δspatial. In some examples, the angular resolution uncertainty can be between 40μm – 100μm, and the range of the collection angle can be between 5° – 10°.

[0179] The properties of the light beam in the system can be configured based on the Gaussian angular divergence. Figure 12An exemplary configuration of an input beam with Gaussian angular divergence according to an example of the present disclosure is shown. System 1200 may be in contact with or near sample 1220. Light may exit system 1200 at position 1206 and may have an incident angle θ 1 (measured with respect to the half-angle divergence θ 12 . In some examples, a portion of the light emitted from the light source may diverge at position 1210 with a portion of the light having an incident angle θ 10 and pass through sample 1220, traveling a length d 21 , arriving at position 1210. Another portion of the light emitted from the light source may also diverge at position 1210 with an incident angle θ 11 and pass through sample 1220, traveling a length d 12 , arriving at position 1210. The light may scatter from position 1210 on the external interface of the system (e.g., the interface where the system contacts the sample) at a scattering angle θ 13 to position 1246. A portion of the scattered light may pass through sample 1220 traveling a length d 12 , and other portions of the scattered light may pass through sample 1220 traveling a length d 22 . A change in the refractive index at the external interface of the system (e.g., the interface where the system contacts the sample) may result in a refraction angle θ 14 .

[0180] The Gaussian angular divergence Δinput may be based on the difference in the optical path lengths between the diverging rays and may be defined as:

[0181] Δinput = d 21 + d 22 - d 11 - d 12 (19)

[0182] According to the sine law:

[0183]

[0184]

[0185]

[0186]

[0187] As the Gaussian angular divergence Δinput increases, the path length uncertainty ΔPL may become dominated by the angular resolution uncertainty Δangular. In some examples, the spatial resolution uncertainty may contribute more than half of the path length uncertainty ΔPL. In some examples, the system may be configured to have a 50° collection angle range that includes 5 - 10 angular bins.

[0188] The tilt of the optical device can be configured based on the light collection efficiency, and the tilt of the optical device can affect the measurement accuracy and the power consumption of the system. By tilting the optical device (i.e., setting the optical axis orientation) such that the collection direction is parallel to the axis of the incident light (i.e., the collection direction faces the incident light direction), the light collection efficiency can be improved. For example, the axis of the incident light can be 45°, and the collection direction can be -45°. In some examples, the tilt of the optical device can be based on the range of the collection angle. For example, the range of the collection angle can be from 0° to -75°, and the collection direction can be -37.5°. In some examples, the range of the collection angle can be from -25° to -70°, and the collection direction can be -47.5°. In some examples, the range of the collection angle can be from -30° to -60°, and the collection direction can be -45°. In some examples, the optical device can include a convex surface, which can be tilted (or eccentric) to address any asymmetry (i.e., bias) within the collection angle range. Compensating for any asymmetry can reduce the magnitude or effect of the optical aberration of the optical device. In some examples, all optical devices can be tiled in the same direction of normal incidence.

[0189] In addition to the optical device, the system performance can also be affected by the properties of one or more other components included in the system. In some examples, the system can include a spacer located between the optical device unit and the optical platform. In some examples, the optical device unit and the optical platform can include single-crystalline silicon. In some examples, the light source, the optical trace, or both can include a silicon waveguide formed on the optical platform. In some examples, the ROIC coupled to the detector can be fabricated on silicon. By configuring one or more of the optical device unit, the optical platform, and the ROIC to include silicon, the thermal expansion of the components can be similar, which can minimize any mechanical weaknesses and can improve the robustness of the system. Additionally, silicon can be a material with many desired properties, such as good mechanical strength, good thermal conductivity, low cost, and good reliability.

[0190] In some examples, the system can include an optical spacer window located between the optical device and the sample. Figure 13A A cross-sectional view of an exemplary system according to an example of the present disclosure is shown, which includes an optical spacer window and a pore layer located between the optical spacer window and the sample. System 1300 can include a light source 1302, an optical device unit 1312, a pore layer 1386, and an optical spacer window 1321, where the optical spacer window 1321 can be in contact with the sample 1320. The light source 1302 can emit light 1352, which exits from the sample 1320. The light, referred to as light 1354, can be reflected from a position 1357 within the sample 1320, transmitted through the pore layer 1386, and reach the optical device unit 1312.

[0191] As Figure 13A shown, placing the pore layer 1386 can result in stray light due to scattering and optical aberrations at the edge interface, which may degrade the imaging properties of the optical device unit 1312. Figure 13B A cross-sectional view of an exemplary system according to an example of the present disclosure is shown, the system including an optical spacer window and a pore layer located between the optical spacer window and the optical device unit. Through the pore layer 1387 located between the optical spacer window 1321 and the optical device unit 1312, light 1354 can propagate to the appropriate optical devices included in the optical device unit 1312, and stray light generated due to scattering at the edge interface can be reduced or eliminated.

[0192] In some examples, the optical spacer window 1321 can be multifunctional and can be configured to provide mechanical support to the optical device. The thickness of the optical device unit 1312 can be configured based on the amount of light bending performed by the optical device unit 1312 and the ability to separate different refractive angles. As the thickness of the optical device unit 1312 decreases, the performance of the optical device unit 1312 increases. However, a decrease in the thickness of the optical device unit 1312 can result in the optical device unit being fragile, expensive, and may require complex manufacturing schemes and low yields. The system can be configured such that the optical spacer window 1321 compensates for the fragility of the thin optical device unit 1312 without degrading the optical performance. In some examples, the thickness of the optical spacer window 1321 can be between 400 μm and 700 μm. In some examples, the thickness of the optical spacer window 1321 can be 650 μm.

[0193] In some examples, the optical spacer window 1321 can be configured to have a thickness such that the heat exchange effect between the sample 1320 and the active components (e.g., detectors, light sources, and electronics) can be reduced. The active components can generate heat and can also be sensitive to any temperature fluctuations, and the temperature of the sample 1320 can vary or can be different from the operating temperature of the active components. Thus, the difference in the sample 1320 temperature and the active component operating temperature can result in a heat exchange effect, which can reduce the measurement accuracy. In some examples, the sample 1320 can be skin, and any temperature difference can cause discomfort if the heat exchange effect is not mitigated.

[0194] In some examples, the optical spacer window 1321 may include an intermediate coating (i.e., a dielectric material having a refractive index between the refractive index of the sample 1320 and the refractive index of the optical device unit 1312). In the absence of an intermediate coating, the optical device unit 1312 or any anti-reflection coating disposed on the optical device unit 1312 would be configured such that there is a high refractive index contrast between the optical device unit 1312 and the sample 1320 or the refraction angle in the system would be reduced. On the other hand, including an intermediate coating can reduce complexity and increase the refraction angle in the system.

[0195] In some examples, the optical spacer window 1321 may include a dielectric material. In some examples, the dielectric material may have higher chemical durability, higher physical durability, or both, compared to the optical device. In some examples, the optical spacer window 1321 may include sapphire. By including an optical spacer window between the optical device and the sample, the system may have higher mechanical strength, higher device durability, and lower heat exchange.

[0196] Including the optical spacer window 1321 can change the way light is distributed between the optical device and the detector pixels in the detector array. However, this change can be accounted for, and the light incident on the detector array can still allow each detector pixel to characterize a trajectory or optical path in the sample. Figure 14AA cross - sectional view of an exemplary system without an optical spacer window according to an example of the present disclosure is shown, and accordingly, the lateral position of light incident at an external interface of the system (e.g., the interface where the system contacts the sample) is determined. System 1400 may include a light source 1402, an optical device unit 1412, a pore layer 1486, and a detector array 1430. The light source 1402 may emit light 1452 that exits the sample 1420 at position 1406. Light 1453, light 1454, and light 1455 may be reflected away at position 1457 within the sample 1420 and may be incident at position 1446 on the external interface of the system (e.g., the interface where the system contacts the sample), and this position 1446 may be at an x distance from position 1406. Light 1453, light 1454, and light 1455 may transmit through the pore layer 1486 and may reach an optical device 1418 included in the optical device unit 1412. The detector array 1430 may include detector pixels 1433, detector pixels 1435, and detector pixels 1437. Light 1453 may be incident on detector pixel 1433, light 1454 may be incident on detector pixel 1435, and light 1455 may be incident on detector pixel 1437. Thus, the optical device 1418, detector pixel 1433, detector pixel 1435, and detector pixel 1437 may be associated with position 1446. In this way, the lateral position of the incident light at the external interface of the system (e.g., the interface where the system contacts the sample) may be associated with the optical device included in the optical device unit.

[0197] Including an optical spacer window may result in determining the lateral position of incident light at an external interface of the system (e.g., the interface where the system contacts the sample) based on the optical device included in the optical device unit and the detector pixels included in the detector array. Figure 14B A cross - sectional view of an exemplary system according to an example of the present disclosure is shown, the system including an optical spacer window and a corresponding determined lateral position of incident light at an external interface of the system (e.g., the interface where the system contacts the sample). System 1490 may include a light source 1402, an optical device unit 1412, a pore layer 1487, an optical spacer window 1421, and a detector array 1430. The light source 1402 may emit light 1452 that exits the system 1490 at position 1406. Light 1452, light 1451, and light 1453 may be reflected away from position 1457 within the sample 1420, may transmit through the pore layer 1487, and may travel through the optical spacer window 1421. In some examples, the scattering angles of light 1452, light 1451, and light 1453 may be different. The sample 1420 may include multiple positions, such as positions 1447, 1448, and 1449 located at the external interface of the system (e.g., the interface where the system contacts the sample). Position 1447 may be at an x distance from position 1406 1At a distance, position 1448 may be located at an x distance from position 1406 2 distance, and position 1449 may be located at an x distance from position 1406 3 distance. Light 1452 may be incident at position 1447, light 1451 may be incident at position 1448, and light 1453 may be incident at position 1449. The detector array 1430 may include detector pixels 1434, detector pixels 1436, and detector pixels 1438. Light 1452 may be incident on detector pixel 1434. Similarly, light 1451 and light 1453 may be incident on detector pixel 1436 and detector pixel 1438, respectively. Detector pixel 1434 may be associated with position 1447, detector pixel 1436 may be associated with position 1448, and detector pixel 1438 may be associated with position 1449. Each position (e.g., position 1447, position 1448, and position 1449) may have a different lateral position, which may be associated with a different scattering angle. In this way, the lateral position of the incident light at the external interface of the system (e.g., the interface where the system contacts the sample) may be associated with the optical devices included in the optical device unit and the detector pixels included in the detector array.

[0198] To determine the association between the optical devices and detector pixels and the lateral position of the incident light and the path length of the optical path at the external interface of the system (e.g., the interface where the system contacts the sample), an exemplary system with an optical spacer window may be simplified, as Figure 14C shown. The angle of the light leaving the system 1450 at position 1406 may be referred to as the exit angle θ 1 , and the angle of the scattered light 1451 from position 1457 may be referred to as the scattering angle θ 2 . The scattering angle θ 2 may be defined as:

[0199]

[0200] where θ CA1 and θ CA2 are the collection angle ranges, and j represents the j-th detector pixel included in the detector array. The corresponding incident angle θ 3 at the spacer-optical device unit interface may be defined as:

[0201]

[0202] where n sample is the refractive index of the sample 1420, and n spacer is the refractive index of the optical spacer window 1421. The distance between position 1447 and the center of the optical device 1418 may be defined as:

[0203] δ(j) = t × tan(θ 3 ) (26)

[0204] where t is the thickness of the optical spacer window 1421. The distance x 1 (i.e., the lateral position of the light) can be defined as:

[0205]

[0206] where m represents the m-th optical device in the optical device unit 1412, and p is the pitch of the optical device 1418. The optical path length PL(j, m) of the light ray can be defined as:

[0207]

[0208] where d 11 is the path length of the light 1452, and d 12 is the path length of the light 1451.

[0209] For example, the optical device 1418 can be configured to collect an angular range θ CA2 equal to 75° and θ CA1 equal to 25°, and the optical devices included in the optical device unit 1412 can be configured to have a pitch of 150 μm. The optical spacer window 1421 can be configured to include sapphire with a refractive index of 1.74 and can be configured to have a thickness of 500 μm. The optical spacer window 1421 can be in contact with a sample having a refractive index of 1.4. The detector array can be configured to have 10 detector pixels coupled to the same optical devices in the optical device unit 1412. The exit angle θ 1 can be 45°, which can cause light rays with a scattering angle of 45° to scatter. The refractive index difference between the optical spacer window 1421 and the sample 1420 can cause the light rays to be incident on the 8th optical device in the optical device unit 1412, and the incident angle θ 3 at the optical spacer - optical device unit interface is equal to 34.7°, and the distance δ is 346 μm. The lateral position x 1 (j, m) of the light ray can be equal to 779 μm, and the optical path length of the light ray can be 1.1 mm.

[0210] Figures 14D to 14EA cross-sectional view of an exemplary system including an optical spacer window according to an example of the present disclosure is shown. As shown in FIG. 14D, including an optical spacer window in the system may allow a single optical device in the optical device unit to collect a range of scattering angles. The range of (different) scattering angles may cause light to be incident at different positions on the external interface of the system (e.g., the interface where the system contacts the sample), together forming a range length. In some examples, the thickness of the optical spacer window may be configured based on the total range length. The optical devices in the optical device unit may collect light from the sample intersection, and thus the aggregate of optical devices in the optical device unit may collect multiple incident angle and exit position arrangements without affecting the loss of light or information.

[0211] As Figure 14E shown, including an optical spacer in the system may also allow light to be emitted into multiple optical devices of the optical device unit at a single position on the external interface of the system (e.g., the interface where the system contacts the sample). Although light and information may be mixed between multiple optical devices and multiple detector pixels, the total information may be the same.

[0212] One or more of the functions described above may be performed, for example, by firmware stored in a memory and executed by a processor or controller. The firmware may also be stored and / or conveyed within any non-transitory computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device such as a computer-based system, a system including a processor, or other systems that can obtain and execute instructions from the instruction execution system, apparatus, or device. In the context of this document, a "non-transitory computer-readable storage medium" may be any medium (excluding signals) that can contain or store a program for use by or in connection with an instruction execution system, apparatus, and device. Non-transitory computer-readable storage media may include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, portable computer disks (magnetic), random access memory (RAM) (magnetic), read-only memory (ROM) (magnetic), erasable programmable read-only memory (EPROM) (magnetic), portable optical discs (such as CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW), or flash memory (such as compact flash cards, secure digital cards), USB memory devices, memory sticks, etc. In the context of this document, a "transmission medium" may be any medium that can convey, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. Transmission-readable media may include, but are not limited to, electronic, magnetic, optical, electromagnetic, or infrared wired or wireless propagation media.

[0213] A system for re-imaging multiple optical paths in a sample is disclosed. The system may include: one or more light sources, each light source being configured to emit a first light and a second light, the first light being incident on the sample and including multiple optical paths, and the second light being incident on a reference object; a modulator configured to alternate between modulating the first light and the second light; one or more optical device units configured to collect at least a portion of the reflection of the first light incident on the sample; a detector array including a plurality of detector pixels and configured to detect at least a portion of the collected reflection of the first light; and a logic unit configured to resolve at least one of the optical path lengths and the incident angles of the multiple optical paths, and configured to associate the detector pixels in the detector array with the optical paths included in the multiple optical paths. In addition or alternatively, in some examples, the system further includes: a plurality of units, each unit including: an emission region configured to reflect or absorb one or more wavelengths different from the wavelength of the light emitted from the one or more light sources; a reference region configured to receive the reflection of the second light; and a measurement region including one or more optical device units, wherein each unit included in the plurality of units is coupled to the measurement region of the sample. In addition or alternatively, in some examples, the reference region includes one or more negative lenses configured to diffuse the reflection of the second light. In addition or alternatively, in some examples, each unit is spaced from another unit by at least 2 mm. In addition or alternatively, in some examples, at least one unit included in the plurality of units includes at least a portion of the measurement region shared by another unit included in the plurality of units. In addition or alternatively, in some examples, each unit includes at least one of the one or more light sources, and at least one unit is configured to measure a region on the sample having a diameter or perimeter less than or equal to 2 mm, and the region on the sample includes at least 70% of the reflection of the first light. In addition or alternatively, in some examples, a first surface of at least one of the one or more optical device units is flat and in contact with the surface of the sample, and a second surface of the at least one of the one or more optical device units is convex. In addition or alternatively, in some examples, the system further includes a spacer located between the one or more optical device units and the sample. In addition or alternatively, in some examples, the spacer includes sapphire. In addition or alternatively, in some examples, the spacer has a thickness between 400 and 700 microns. In addition or alternatively, in some examples, the system further includes a pore layer located between the spacer and the one or more optical device units.In addition or alternatively, in some examples, the system further includes a pore layer configured to provide access to one or more optical paths having a path length in a first path length range and an incident angle in a first angle range to one or more optical device units, and further configured to reject one or more optical paths having a path length in a second path length range different from the first path length range and an incident angle in a second angle range different from the first angle range. In addition or alternatively, in some examples, the pore layer is on the same layer as at least the one or more optical device units. In addition or alternatively, in some examples, the one or more optical device units include a plurality of recessed optical devices. In addition or alternatively, in some examples, the system further includes a coupler located between the one or more light sources and the sample and also between the one or more light sources and the reference object, the coupler being configured to split the light emitted from the one or more light sources into first light and second light, the intensity of the first light being greater than the intensity of the second light. In addition or alternatively, in some examples, the system further includes: a first output coupler including a bridge, the first output coupler being configured to receive the first light and redirect the first light toward the sample; and a second output coupler including a bridge, the second coupler being configured to receive the second light and redirect the second light toward the reference object. In addition or alternatively, in some examples, the system further includes one or more optical devices coupled to the first output coupler and the sample, a first surface of the one or more optical devices being in contact with a surface of the first output coupler. In addition or alternatively, in some examples, the system further includes at least one of one or more integrated tuning elements, one or more multiplexers, optical wiring, one or more waveguides, and an integrated circuit included in a silicon photonics chip. In addition or alternatively, in some examples, the beam size of at least one of the one or more light sources is between 100 and 300 microns. In addition or alternatively, in some examples, the thickness of at least one of the one or more optical device units is between 100 and 300 microns. In addition or alternatively, in some examples, the system may be included in a package having a size less than 1 cm. 3 In a package.

[0214] A system is disclosed. The system may include: one or more light sources, each light source being configured to emit a first light and a second light, the first light being directed towards an external interface of the system and including a plurality of optical paths, and the second light being incident on a reference object; one or more first optical devices configured to collect at least a portion of the reflection of the first light incident on a sample and change the angle of the first light; one or more second optical devices configured to receive the first light from the one or more first optical devices and focus the first light onto a detector array; and the detector array including a plurality of detector pixels and being configured to detect at least a portion of the focused first light from the one or more second optical devices. In addition or alternatively, in some examples, the system further includes: a plurality of groups, each group including: an emission region configured to reflect or absorb one or more wavelengths different from the wavelength of the light emitted from the one or more light sources; a reference region configured to receive the reflection of the second light; and a measurement region including one or more first optical devices. In addition or alternatively, in some examples, each group includes an emission region, a reference region, and a plurality of measurement regions. In addition or alternatively, in some examples, at least one group shares at least a portion of a measurement region with another group. In addition or alternatively, in some examples, a first surface of at least one first optical device is flat and is located at the external interface of the system, and a second surface of the at least one optical device is convex. In addition or alternatively, in some examples, the system further includes: a pore layer configured to allow one or more first optical paths to pass through the one or more first optical devices, the one or more second optical devices, or both, the one or more first optical paths having a path length within a first path length range, wherein the pore layer is further configured to reject one or more second optical paths having a path length within a second path length range different from the first path length range. In addition or alternatively, in some examples, the system further includes a pore layer configured to allow one or more first optical paths to pass through the one or more first optical devices, the second layer of optical devices, or both, the one or more first optical paths having an incident angle within a first angle range, wherein the pore layer is further configured to reject one or more second optical paths having an incident angle within a second angle range different from the first angle range. In addition or alternatively, in some examples, the system further includes a coupler located between the one or more light sources and the external interface of the system, and the coupler is also located between the one or more light sources and the reference object, and wherein the coupler is configured to split the light emitted from the one or more light sources into a first light and a second light, wherein the intensity of the first light is greater than the intensity of the second light.In addition or alternatively, in some examples, the system further includes: a first output coupler including a bridge, the first output coupler being configured to receive a first light and redirect the first light toward an external interface of the system; and a second output coupler including a bridge, the second coupler being configured to receive a second light and redirect the second light toward a reference object. In addition or alternatively, in some examples, the system further includes one or more third optical devices coupled to the first output coupler and the external interface of the system, wherein a first surface of the one or more third optical devices contacts a surface of the first output coupler. In addition or alternatively, in some examples, the system further includes at least one of one or more integrated tuning elements, one or more multiplexers, optical wiring, one or more waveguides, and an integrated circuit, wherein the one or more integrated tuning elements are included in a silicon photonics chip. In addition or alternatively, in some examples, each detector pixel is associated with a first optical device and a second optical device. In addition or alternatively, in some examples, each first optical device is associated with a second optical device and a plurality of the plurality of detector pixels. In addition or alternatively, in some examples, one or more of the first optical devices include a material different from a material included in one or more of the second optical devices.

[0215] An optical system for determining one or more properties of a sample is disclosed. In some examples, the optical system includes: a first optical device unit disposed on a first substrate and configured to receive and redirect light reflected from a first light incident on the sample, the first optical device unit including a plurality of first optical devices, each first optical device coupled to a detector pixel included in a detector array and an optical path included in a plurality of optical paths. In addition or alternatively, in some examples, a surface of the first optical device unit is in contact with a surface of the sample and is further configured to focus the reflection of the first light toward a surface of the detector array. In addition or alternatively, in some examples, the plurality of first optical devices are configured to have an inclination oriented in the same direction with respect to normal incidence. In addition or alternatively, in some examples, the system further includes a second optical device unit disposed on a second substrate and configured to receive and focus the first light from the first optical device unit, the second optical device unit including a plurality of second optical devices, each second optical device coupled to a first optical device included in the first optical device unit. In addition or alternatively, in some examples, the first optical device unit is attached to the second optical device unit by a plurality of mechanical registration features formed on the first optical device unit, the second optical device unit, or both. In addition or alternatively, in some examples, each first optical device includes a prism and is configured to have one or more properties different from other first optical devices. In addition or alternatively, in some examples, at least one of the first optical devices includes silicon. In addition or alternatively, in some examples, each first optical device is coupled to a plurality of detector pixels included in a detector array. In addition or alternatively, in some examples, at least one of the plurality of first optical devices is configured to have a collection angle range equal to 50° and is configured to have 5 to 10 angular intervals. In addition or alternatively, in some examples, at least one of the plurality of first optical devices is configured to have a collection angle range centered at 45°.

[0216] An optical system is disclosed. The optical system may include: one or more first optical devices disposed on a first substrate and configured to receive and redirect first light; one or more second optical devices disposed on a second substrate and configured to receive the first light from the one or more first optical devices, the one or more second optical devices further configured to focus the received first light; and a pore layer including one or more openings and configured to allow a first portion of incident light to pass through and block a second portion of the incident light, wherein the pore layer is located on the same layer as the one or more first optical devices or the one or more second optical devices. Additionally or alternatively, in some examples, the pore layer allows a first portion of the incident light to pass through based on the angle of incidence of the incident light. Additionally or alternatively, in some examples, the pore layer allows a first portion of the incident light to pass through based on the path length. Additionally or alternatively, in some examples, the system further includes: a second pore layer located on the same layer as the one or more second optical devices, wherein the first pore layer is located on the same layer as the one or more first optical devices. Additionally or alternatively, in some examples, the pore layer is a lithographic pattern disposed on the surface of the one or more first optical devices or the one or more second optical devices. Additionally or alternatively, in some examples, the system further includes: a third optical device located on the same layer as the one or more second optical devices, wherein the third optical device is configured to receive light from a first surface of the system and direct the light to a second surface of the system, wherein the one or more first optical devices and the one or more second optical devices are configured to receive the first light from the second surface of the system.

[0217] A method for determining one or more properties of a sample is disclosed. In some examples, the method includes: determining a first angle of incidence of a first light at a first interface, the first interface including the sample and a spacer, the first light being emitted from a light source; determining a second angle of incidence of a second light at the first interface, the second light being a reflection of the first light and including first information; determining a third angle of incidence of a third light at a second interface, the second interface including the spacer and one or more optical device units; and determining a path length of an optical path based on the first angle of incidence, the second angle of incidence, and the third angle of incidence. Additionally or alternatively, in some examples, the system further includes: determining a fourth angle of incidence of a fourth light at the first interface, the fourth light being a reflection of the first light and including second information, the first light and the second light being from the same position in the sample, wherein the second light is incident at a first position along the first interface, and the fourth light is incident at a second position along the second interface, the second position being different from the first position, and wherein the second light and the fourth light are collected by a first optical device; and determining third information based on an aggregation of the first information and the second information. Additionally or alternatively, in some examples, the method further includes: determining a fourth angle of incidence of a fourth light at the first interface, the fourth light being a reflection of the first light and including second information, wherein the second light and the fourth light are incident at a first position along the first interface and at a second position along the second interface, and wherein the second light and the fourth light are collected by different optical devices included in the one or more optical device units; and determining third information based on an aggregation of the first information and the second information. Additionally or alternatively, in some examples, the method further includes: associating the optical path with an optical device included in the one or more optical device units and a detector pixel included in a detector array, wherein determining the path length of the optical path is further based on a collection angle range of the optical device and a thickness of the spacer. Additionally or alternatively, in some examples, the optical path is included in a plurality of optical paths, each optical path having a set of information, the set of information including a path length, an angle of incidence, and a certain position in the sample, wherein each set of information is different from other sets of information included in the plurality of optical paths.

[0218] While the disclosed examples have been described in full with reference to the accompanying drawings, it should be noted that various changes and modifications will become apparent to those skilled in the art. It should be understood that such changes and modifications are considered to be included within the scope of the disclosed examples as defined by the appended claims.

Claims

1. A system for determining an attribute of a sample, the system comprising: one or more light sources; a detector array; and a first substrate, comprising: illumination optics configured to receive light emitted by the one or more light sources and redirect the light towards the sample; and a first collection optic configured to receive at least a portion of the returned light of the light and redirect the light towards the detector array; a second substrate, comprising: a second collection optic including a lens and configured to receive the at least a portion of the returned light of the light and redirect the at least a portion of the returned light of the light to the first collection optic, wherein: the illumination optics and the first collection optic are formed on one or more surfaces of the first substrate; the detector array is configured to detect the light redirected by the first collection optic and generate one or more signals indicative of the attribute of the sample.

2. The system according to claim 1, wherein the second collection optic is integrated into the second substrate.

3. The system according to claim 1, further comprising: a medium located between the first substrate and the second substrate, wherein the medium has a refractive index such that an angle at which the light exits the first collection optic is reduced relative to an angle at which the light is incident on the second collection optic.

4. The system according to claim 1, furthercomprising: a medium located between the first substrate and the detector array, wherein the medium is a conformal insulating material providing mechanical support.

5. The system according to claim 1, furthercomprising: a pore layer including one or more openings configured to selectively allow the light to pass through to the first collection optic.

6. The system according to claim 5, wherein the pore layer is formed on one or more surfaces of the second substrate.

7. The system according to claim 5, wherein the pore layer is formed on one or more surfaces of the first substrate.

8. The system according to claim 5, wherein the pore layer is positioned away from the first substrate by a focal length.

9. The system according to claim 1, wherein the first substrate is located between the sample and the detector array.

10. The system according to claim 1, wherein the first collection optic is integrated into the first substrate.

11. The system according to claim 1, furthercomprising: an outer coupler configured to: receive the light emitted by the one or more light sources; and redirect the light towards the illumination optics, wherein the outer coupler contacts one of the one or more surfaces of the first substrate.

12. The system according to claim 11, wherein the outer coupler is formed on a third substrate and the third substrate is closer to the first substrate than the detector array.

13. A method for determining an attribute of a sample, the method comprising: ​ ​ ​ Receiving light emitted by one or more light sources using an illumination optical device and redirecting the light towards the sample, the illumination optical device being formed on one or more surfaces of a first substrate; Receiving at least a portion of the return light of the light using a second collection optical device formed on one or more surfaces of a second substrate, the second collection optical device including a lens; Redirecting the at least a portion of the return light of the light to a first collection optical device using the second collection optical device; Receiving at least a portion of the return light of the light using a first collection optical device and redirecting the light towards a detector array, the first collection optical device being formed on the one or more surfaces of the first substrate; Detecting the light redirected by the first collection optical device using the detector array; And Generating one or more signals indicative of at least some properties of the sample using the detector array.

14. The method according to claim 13, further comprising: Reducing the angle by which the light is redirected by the first collection optical device.

15. The method according to claim 13, further comprising: Using a pore layer to selectively allow the light redirected by the first collection optical device to pass through.

16. The method according to claim 13, further comprising: Receiving the light redirected by the first collection optical device and redirecting the light towards the second collection optical device.

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