LED light source systems for interferometry applications

Abstract

Light source systems comprising light-emitting diodes, instruments comprising such light sources, and associated methods are generally described. In some embodiments, a light source system described herein has one or more features that facilitate the use of light-emitting diodes therein. In some embodiments, a light source system described herein has one or more features that allow for light supplied by the light source system to serve as an internal standard that may be employed to normalize the intensity of light received by an optical detector during an optical measurement. Some light source systems described herein may be particularly suitable for supplying light to employed in an interferometry measurement.

Description

[0001] LED LIGHT SOURCE SYSTEMS FOR INTERFEROMETRY APPLICATIONS

[0002] RELATED APPLICATIONS

[0003] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63 / 703,504, filed October 4, 2024, and entitled “LED Light Source Systems for Interferometry Applications,” which is incorporated herein by reference in its entirety for all purposes.

[0004] FIELD

[0005] Light-emitting diode light source systems for interferometry applications, associated instruments, and associated methods, are generally described.

[0006] BACKGROUND

[0007] Light source systems may be employed to generate light for use in optical measurements, such as interferometry measurements. However, some light source systems may exhibit spectral ranges that are undesirably narrow, exhibit undesirably low spectrum stability, and / or exhibit undesirably low lifespans.

[0008] Accordingly, new light source systems, associated instruments, and methods of use thereof would be beneficial.

[0009] SUMMARY

[0010] The present disclosure generally describes light source systems, associated instruments, and methods. The subject matter described herein involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0011] Paragraph 1 : In some embodiments, an instrument is provided. The instrument comprises a housing configured to receive a probe at a first location, an optical detector, and a light source system. The light source system comprises a light-emitting diode configured to emit light over a first wavelength range, a spectral broadener positioned optically between the first location and the light-emitting diode, and a temperature controller configured to control

[0012] 1

[0013] #14430292vl temperatures of the light-emitting diode and the spectral broadener. The light source system is configured to supply light emitted by the spectral broadener to the first location.

[0014] Paragraph 2: In some embodiments, an instrument is provided that comprises a housing configured to receive a probe at a first location, an optical detector, a light source system, and an optical multiplexer. The light source system comprises a light-emitting diode configured to emit light. The optical multiplexer is configured to divide light supplied thereto by the light source system into a first portion and a second portion. The optical multiplexer is configured to supply the first portion to the first location. The optical multiplexer is configured to supply the second portion to the optical detector along a pathway that does not pass through the first location.

[0015] Paragraph 3: In some embodiments, a method is provided. The method comprises emitting light from a light-emitting diode over a first wavelength range, impinging the light emitted from the light-emitting diode on a spectral broadener, and supplying light emitted by the spectral broadener to a probe. The temperatures of the light-emitting diode and the spectral broadener are controlled by a temperature controller such that they vary by no more than 1.0 °C.

[0016] Paragraph 4: In some embodiments, a method is provided that comprises emitting light from a light source system that comprises a light-emitting diode configured to emit light, dividing the light emitted from the light source system into a first portion and a second portion, supplying the first portion to a probe, and supplying the second portion to an optical detector along a pathway that does not pass through the probe.

[0017] Paragraph 5: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a cable.

[0018] Paragraph 6: In some embodiments, in an instrument or method of any preceding Paragraph, the cable comprises a fiber-optic bundle.

[0019] Paragraph 7: In some embodiments, in an instrument or method of any preceding Paragraph, the cable is configured to supply light emitted by the light source system to the first location.

[0020] Paragraph 8: In some embodiments, in an instrument or method of any preceding Paragraph, the spectral broadener is configured to absorb light having a wavelength within the first wavelength range, and, upon such absorption, emit light over a second wavelength range, and wherein the light emitted over the second wavelength range is supplied to the probe by the cable.

[0021] 2

[0022] #14430292vl Paragraph 9: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a second cable.

[0023] Paragraph 10: In some embodiments, in an instrument or method of any preceding Paragraph, the second cable comprises a fiber-optic bundle.

[0024] Paragraph 11 : In some embodiments, in an instrument or method of any preceding Paragraph, the second cable is configured to supply light transmitted through the probe to the optical detector.

[0025] Paragraph 12: In some embodiments, in an instrument or method of any preceding Paragraph, light transmitted through the probe is supplied to the optical detector by the cable.

[0026] Paragraph 13: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a focusing element positioned optically between the light source system and the cable.

[0027] Paragraph 14: In some embodiments, in an instrument or method of any preceding Paragraph, the focusing element is a lens.

[0028] Paragraph 15: In some embodiments, in an instrument or method of any preceding Paragraph, the focusing element is transmissive.

[0029] Paragraph 16: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises two or more focusing elements positioned between the light source system and the cable.

[0030] Paragraph 17: In some embodiments, in an instrument or method of any preceding Paragraph, the focusing elements are lenses.

[0031] Paragraph 18: In some embodiments, in an instrument or method of any preceding Paragraph, the focusing elements are transmissive.

[0032] Paragraph 19: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a reflective element positioned optically between the light source system and the cable.

[0033] Paragraph 20: In some embodiments, in an instrument or method of any preceding Paragraph, the reflective element is a mirror.

[0034] Paragraph 21 : In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises two or more reflective elements positioned between the light source system and the cable.

[0035] 3

[0036] #14430292vl Paragraph 22: In some embodiments, in an instrument or method of any preceding Paragraph, the reflective elements are mirrors.

[0037] Paragraph 23 : In some embodiments, in an instrument or method of any preceding Paragraph, the probe is an optical probe.

[0038] Paragraph 24: In some embodiments, in an instrument or method of any preceding Paragraph, the probe comprises an optical fiber.

[0039] Paragraph 25: In some embodiments, in an instrument or method of any preceding Paragraph, the spectral broadener is configured to absorb light having a wavelength within the first wavelength range, and, upon such absorption, emit light over a second wavelength range.

[0040] Paragraph 26: In some embodiments, a method of any preceding Paragraph further comprises absorbing the light emitted from the light-emitting diode with the spectral broadener, thereby stimulating the emission of light over a second wavelength range.

[0041] Paragraph 27: In some embodiments, in an instrument or method of any preceding Paragraph, the second wavelength range comprises a wavelength that is outside the first wavelength range.

[0042] Paragraph 28: In some embodiments, in an instrument or method of any preceding Paragraph, the second wavelength range extends from 190 nm to 1200 nm.

[0043] Paragraph 29: In some embodiments, in an instrument or method of any preceding Paragraph, the spectral broadener is configured to emit light over the second wavelength range via luminescence.

[0044] Paragraph 30: In some embodiments, in an instrument or method of any preceding Paragraph, the spectral broadener is configured to emit light over the second wavelength range via phosphorescence.

[0045] Paragraph 31 : In some embodiments, in an instrument or method of any preceding Paragraph, the temperature controller is configured to maintain the temperature of the lightemitting diode such that it varies by no more than 1 °C.

[0046] Paragraph 32: In some embodiments, in an instrument or method of any preceding Paragraph, the temperature controller is configured to maintain the temperature of the spectral broadener such that it varies by no more than 1 °C.

[0047] 4

[0048] #14430292vl Paragraph 33: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a second temperature controller configured to control temperature of the optical detector.

[0049] Paragraph 34: In some embodiments, in an instrument or method of any preceding Paragraph, the light-emitting diode is thermally insulated from the optical detector.

[0050] Paragraph 35: In some embodiments, in an instrument or method of any preceding Paragraph, the light-emitting diode is thermally insulated from the spectral broadener.

[0051] Paragraph 36: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a current stabilizer that is configured to maintain the current passing through the light-emitting diode.

[0052] Paragraph 37: In some embodiments, in an instrument or method of any preceding Paragraph, the optical detector comprises a transmissive collimator positioned to collimate light supplied by the second cable.

[0053] Paragraph 38: In some embodiments, in an instrument or method of any preceding Paragraph, the optical detector comprises a diffraction grating positioned to disperse light collimated by the transmissive collimator.

[0054] Paragraph 39: In some embodiments, a method of any preceding Paragraph further comprises detecting an optical signal generated from the first portion of the light by an optical detector.

[0055] Paragraph 40: In some embodiments, in an instrument or method of any preceding Paragraph, the light emitted from the light source system comprises light emitted by the lightemitting diode.

[0056] Paragraph 41 : In some embodiments, in an instrument or method of any preceding Paragraph, the light source system comprises a spectral broadener, and wherein the light emitted from the light source system comprises light emitted by the spectral broadener.

[0057] Paragraph 42: In some embodiments, a method as in any preceding Paragraph further comprises detecting the second portion of the light by the optical detector.

[0058] Paragraph 43 : In some embodiments, a method as in any preceding Paragraph further comprises determining whether the light emitted from the light source system varies with time based on the detection of the second portion of the light.

[0059] 5

[0060] #14430292vl Paragraph 44: In some embodiments, a method as in any preceding Paragraph further comprises detecting the first portion of the light, and wherein detecting the second portion of light comprises measuring an intensity of the second portion of the light, and wherein detecting the first portion of the light comprises measuring an intensity of the first portion of the light.

[0061] Paragraph 45: In some embodiments, a method as in any preceding Paragraph further comprises normalizing the measured intensity of the second portion of the light by the measured intensity of the first portion of the light.

[0062] Paragraph 46: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a plurality of light-emitting diodes.

[0063] Paragraph 47: In some embodiments, in an instrument or method of any preceding Paragraph, the plurality of light-emitting diodes comprises light-emitting diodes that are configured to emit light over different wavelength ranges.

[0064] Paragraph 48: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a light diffuser positioned optically between the light source system and the first location.

[0065] Paragraph 49: In some embodiments, in an instrument or method of any preceding Paragraph, the light diffuser is configured to receive and mix the light from a plurality of lightemitting diodes positioned in the instrument.

[0066] Paragraph 50: In some embodiments, in an instrument or method of any preceding Paragraph, the instrument further comprises a light diffuser positioned between the light source system and the optical multiplexer.

[0067] Paragraph 51 : In some embodiments, in an instrument or method of any preceding Paragraph, the light diffuser comprises a light pipe.

[0068] Paragraph 52: In some embodiments, in an instrument or method of any preceding Paragraph, the light pipe is a hexagonal rod.

[0069] Paragraph 53: In some embodiments, in an instrument or method of any preceding Paragraph, the light diffuser comprises a holographic diffuser.

[0070] Paragraph 54: In some embodiments, an instrument or method of any preceding Paragraph is configured to perform and / or is capable of performing the method of any preceding Paragraph.

[0071] 6

[0072] #14430292vl Other advantages and novel features of the present invention will become apparent from the following detailed description of various non-limiting embodiments of the invention when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control. If two or more documents incorporated by reference include conflicting and / or inconsistent disclosure with respect to each other, then the document having the later effective date shall control.

[0073] BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. In the figures:

[0075] FIGs. 1-5 show non-limiting examples of light source systems, in accordance with some embodiments;

[0076] FIGs. 6 and 7 show non-limiting examples of exemplary instruments, in accordance with some embodiments;

[0077] FIGs. 8, 9A, and 9B show exemplary methods, in accordance with some embodiments;

[0078] FIGs. 10 and 11 show different views of a light pipe, in accordance with some embodiments;

[0079] FIG. 12 shows the supply of light directly to a cable from a light source system, in accordance with some embodiments;

[0080] FIG. 13 shows the supply of light to a cable that interacts with one component after being emitted from the light source system and before impinging on the cable, in accordance with some embodiments;

[0081] FIG. 14 shows the supply of light to a cable that interacts with two components after being emitted from the light source system and before impinging on the cable, in accordance with some embodiments;

[0082] 7

[0083] #14430292vl FIGs. 15 and 16 show non-limiting examples of probes, in accordance with some embodiments;

[0084] FIG. 17 depicts schematically one example of a process by which light comprising both an amount of the light that has been reflected from an interface internal to a probe and an amount of light that has been reflected from the end of a first probe can be generated, in accordance with some embodiments;

[0085] FIGs. 18 and 19 depict exemplary instruments, in accordance with some embodiments;

[0086] FIG. 20 shows a mechanical drawing of the exemplary light pipe, in accordance with some embodiments;

[0087] FIG. 21 shows a photograph of an exemplary light pipe, in accordance with some embodiments;

[0088] FIG. 22 shows a mechanical drawing of an exemplary holographic diffuser, in accordance with some embodiments;

[0089] FIG. 23 shows a photograph of four exemplary holographic diffusers, in accordance with some embodiments; and

[0090] FIGs. 24 and 25 show experimental data comparing the performance of different light diffusers, in accordance with some embodiments.

[0091] DETAILED DESCRIPTION

[0092] Light source systems comprising light-emitting diodes, instruments comprising such light sources, and associated methods are generally described. In some embodiments, a light source system described herein has one or more features that facilitate the use of light-emitting diodes therein. In some embodiments, a light source system described herein has one or more features that allow for light supplied by the light source system to serve as an internal standard that may be employed to normalize the intensity of light received by an optical detector during an optical measurement. Some light source systems described herein may be particularly suitable for supplying light to be employed in an interferometry measurement.

[0093] One example of a feature that can facilitate the use of light-emitting diodes in a light source system is a spectral broadener. Some measurement techniques, such as some interferometry techniques, are benefited by the use of light sources that emit light over relatively broad wavelength ranges. Such broad wavelength ranges may allow for light having a broad

[0094] 8

[0095] #14430292vl wavelength range to impinge on a material in a manner that results in the generation of an optical signal. In some such embodiments, it may be desirable for the variation of the optical signal with wavelength to be measured across a relatively broad wavelength range. Light-emitting diodes, although having other desirable properties, may emit light over relatively narrow wavelength ranges. The use of a spectral broadener in combination with a light-emitting diode may desirably allow for the wavelength range of light supplied by light-emitting diodes to be broadened prior to impinging on a material in a manner that results in the generation of an optical signal.

[0096] Another example of a feature that can facilitate the use of light-emitting diodes in a light source system is a temperature controller. Some light-emitting diodes may undesirably exhibit shifts with temperature in the wavelength range over which they emit. In some embodiments, temperature controllers may be employed to prevent and / or mitigate such wavelength range shifts by maintaining the temperature of light-emitting diodes present in a light source system within a relatively narrow range.

[0097] One example of a feature that allows for light supplied by the light source system to serve as an internal standard is an optical multiplexer. An optical multiplexer may be employed to divide light supplied by a light source system into two portions: one of which is employed as the internal standard and the other of which is allowed to impinge on a material to generate an optical signal. The first portion of light may serve as an internal standard for the generated optical signal, thereby desirably reducing the need to perform costly and time-intensive calibration procedures and allowing for highly accurate normalization of the intensity of the light present in the optical signal. Additionally, when both the first portion of light and the optical signal are detected with the same detector, this normalization may account variations in light intensity that depend both on variations in the light intensity supplied and on variations in the optical detector’s ability to detect light (e.g., across wavelength and / or across time). This may be beneficial when a light source system emits light that has a wavelength-dependent intensity and / or an instrument comprises an optical detector that detects light with a wavelengthdependent efficiency.

[0098] FIG. 1 shows one non-limiting example of a light source system. The light source system 100 shown in FIG. 1 comprises a light-emitting diode 102, a spectral broadener 104, and a temperature controller 106. In some embodiments, a light-emitting diode present in a light

[0099] 9

[0100] #14430292vl source system is configured to emit light. The light source system may further comprise one or more other components that assist with causing light emitted from the light-emitting diode, and / or light whose emission was stimulated therefrom, to have one or more desirable features. Two examples of such components (i.e., a spectral broadener and a temperature controller) are depicted in FIG. 1. It is also possible for a light source system to comprise a light-emitting diode but lack either or both of a spectral broadener and a temperature controller.

[0101] In some embodiments, in a light source system comprising both a light-emitting diode and a spectral broadener, the spectral broadener is positioned optically between the light-emitting diode and a location at which light is employed to perform an optical measurement (e.g., a location at which light impinges on a material in a manner that results in the generation of an optical signal, a location at which a probe is positioned, a location configured to receive a probe). In such embodiments, the spectral broadener may interact with the light emitted by the lightemitting diode prior to such light reaching that location. This interaction may comprise absorbing light emitted by the light-emitting diode, emitting light (e.g., due to stimulation caused by absorbing light emitted by the light-emitting diode, due to other stimulation), and / or broadening the wavelength range of the light emitted by the light-emitting diode. When light interacts with a spectral broadener and / or is emitted by a spectral broadener, it may have a different (e.g., broader) spectral range than the light emitted by the light-emitting diode. In such embodiments, this interaction may result in the transmission of light to the location at which the optical measurement is performed that has a different spectrum than the light emitted by the light-emitting diode. It is also possible for a spectral broadener to transmit some of the light emitted by the light-emitting diode.

[0102] In some embodiments, in a light source system comprising both a light-emitting diode and a temperature controller, the temperature controller may be configured to control the temperature of the light-emitting diode and / or the spectral broadener. Such temperature controllers may desirably reduce or eliminate any temperature-induced shifts in the wavelength ranges emitted by these components and / or any temperature-induced shifts in the wavelength range absorbed by the spectral broadener.

[0103] In some embodiments, a light source system comprises more than one light-emitting diode (e.g., a plurality of light-emitting diodes). FIG. 2 shows one non-limiting example of a light source system 200 comprising a plurality of light-emitting diodes 202A-202C. The light

[0104] 10

[0105] #14430292vl source system shown in FIG. 2 further comprises a temperature controller 206. As shown in FIG. 2, the temperature controller 206 may be configured to control the temperature of one or more of the light-emitting diodes in the plurality of light-emitting diodes. In some embodiments, a temperature controller controls the temperature of two or more light-emitting diodes in a plurality of light-emitting diodes independently from each other.

[0106] When a light source system comprises a plurality of light-emitting diodes, the number of light-emitting diodes in the plurality may be selected as desired. For instance, a plurality of light-emitting diodes may comprise two, three, four, five, or more light-emitting diodes.

[0107] A plurality of light-emitting diodes may comprise two or more light-emitting diodes that are configured to emit light over different wavelength ranges. Without wishing to be bound by any particular theory, this may be desirable in order to allow for light spanning a broader wavelength range to be supplied to a location at which light is employed to perform an optical measurement e.g., a location at which light impinges on a material in a manner that results in the generation of an optical signal, a location at which a probe is positioned, a location configured to receive a probe) without the need for a spectral broadener. For instance, a plurality of lightemitting diodes may together, when the emissions from all of the light-emitting diodes are mixed, emit light over a wavelength range that is sufficiently broad to perform an optical measurement of interest. In some embodiments, a plurality of light-emitting diodes comprises no two light-emitting diodes that emit light over identical wavelength ranges.

[0108] It is also possible for a plurality of light-emitting diodes to comprise two or more lightemitting diodes that emit light over identical wavelength ranges. Finally, it is possible for a plurality of light-emitting diodes to consist of light-emitting diodes that emit light over identical wavelength ranges. Such designs may be desirable in order to increase the intensity of light emitted over a certain wavelength range (e.g., when that wavelength range has particular utility for an optical measurement and / or for stimulating the emission of light from a spectral broadener).

[0109] In some embodiments, a light source system comprises a plurality of light-emitting diodes and also further comprises both a temperature controller and a spectral broadener. This is depicted schematically in FIG. 3, in which the light source system 300 comprises a plurality of light-emitting diodes 302A-302C, a spectral broadener 304, and a temperature controller 306.

[0110] 11

[0111] #14430292vl In some embodiments, a light source system comprises a light diffuser that is configured to receive and mix light from a plurality of light-emitting diodes. The light diffuser may be configured to receive the light by being positioned in a location that is supplied with light by the plurality of light-emitting diodes (e.g., a position along the pathway traveled by light emitted by the plurality of light-emitting diodes). FIG. 4 shows one non-limiting example of a light source system 400 comprising a plurality of light-emitting diodes 402A-402C and a light diffuser 408. The light source system 400 further comprises a spectral broadener 404 and a temperature controller 406. Light diffusers may be positioned optically between the plurality of lightemitting diodes and a spectral broadener (e.g., as shown in FIG. 4), optically between the plurality of light-emitting diodes and a location at which light is employed to perform an optical measurement (e.g., a location at which light impinges on a material in a manner that results in the generation of an optical signal, a location at which a probe is positioned, a location configured to receive a probe), and / or optically between the plurality of light-emitting diodes and a component external to the light source system (e.g., a location at which light is employed to perform an optical measurement as previously described, an optical multiplexer, an optical detector). In some embodiments, a spectral broadener is positioned optically between a plurality of lightemitting diodes and a light diffuser (not shown). It is also possible for light diffusers to be present in light source systems lacking spectral broadeners (also not shown).

[0112] Mixing effected by a light diffuser may enhance the uniformity of the light that passes through the light diffuser in one or more ways. For instance, it may enhance the spatial uniformity (e.g., across the cross-section of the light perpendicular to the direction of its propagation) of the intensity of the light and / or of one or more wavelengths of light. As one example, it may result in mixing between light emitted from light-emitting diodes that are configured to emit light over different wavelength ranges, mixing this light into a more-uniform and / or uniform beam of light.

[0113] In some embodiments, a light source system comprises current stabilizer. FIG. 5 shows one non-limiting example of a light source system 500 comprising a current stabilizer 510. The light source system 500 further comprises a light-emitting diode 502, a spectral broadener 504, and a temperature controller 506. It is also possible for light source systems comprising further components, like the light source systems shown in FIGs. 1-4, to also comprise a current stabilizer. When present, a current stabilizer may stabilize the current that is supplied to and / or

[0114] 12

[0115] #14430292vl passes through a light-emitting diode and / or a plurality of light-emitting diodes. Without wishing to be bound by any particular theory, it is believed that some light-emitting diodes may be particularly sensitive to fluctuations in applied voltage and / or may experience large changes in the amount of current passing therethrough in response to relatively small fluctuations in the applied voltage. Additionally, some light-emitting diodes may emit light with an intensity that is proportional to the current passing therethrough. For these reasons, it may be desirable to supply such light-emitting diodes with a relatively constant current in order to enhance the stability of the light emitted thereby. For instance, the intensity of light emitted by a light-emitting diode may be particularly sensitive to such fluctuations.

[0116] In some embodiments, an instrument described herein comprises a light source system and further comprises one or more further components. FIG. 6 shows one example of an exemplary instrument 612 that comprises a light source system 600, an optical detector 614, and a housing 616. In some embodiments, an instrument described herein is capable of performing an optical measurement and / or configured to perform an optical measurement in which light supplied by the light source system impinges on a material that generates an optical signal that is detected by an optical detector. Instruments like those shown in FIG. 6 may include a variety of light source systems (e.g., a light source system having one or more of the features shown in FIGs. 1-5 and / or described elsewhere herein), optical detectors (e.g., an optical detector as described elsewhere herein), and housings (e.g., a housing as described elsewhere herein).

[0117] In some embodiments, a housing present in an instrument is configured to receive a probe at a first location. The first location may be a location that is configured to be supplied by light from a light source system (e.g., from a light-emitting diode and / or plurality of light-emitting diodes therein, from a spectral broadener therein, such as a spectral broadener positioned between the light-emitting diode and the first location). In such embodiments, the instrument may be configured such that, when a probe is present in the housing, light emitted from the light source system is supplied to the probe. Such light may be transmitted through the probe (e.g., to impinge on a material in a manner that results in the generation of an optical signal) and / or may interact with the probe in a manner that generates an optical signal. In some embodiments, an instrument may be configured such that, when a probe is present in the housing, an optical signal (e.g., an optical signal generated by light transmitted through a probe, an optical signal generated by an interaction between light and a probe) is supplied to an optical detector.

[0118] 13

[0119] #14430292vl Some embodiments are directed to instruments comprising a probe. In such embodiments, the probe may be positioned in the housing (e.g., at a first location as described elsewhere herein). The housing may mechanically support the probe, may fix the position of the probe (e.g., via mating, a pressurized fit, clamps, a holder, an adhesive, etc.) at a location (e.g., a first location), and / or may be configured to translate and / or be capable of translating the probe. In some embodiments, a housing is configured such that a probe may be reversibly inserted into and / or removed therefrom (e.g., at a first location as described elsewhere herein).

[0120] In some embodiments, an instrument comprises an optical multiplexer. FIG. 7 shows one non-limiting example of an instrument 712 comprising an optical multiplexer 718. The instrument 712 also further comprises a light source system 700, an optical detector 714, and a housing 716. Instruments like those shown in FIG. 7 may include a variety of light source systems (e.g., a light source system having one or more of the features shown in FIGs. 1-5 and / or described elsewhere herein), optical detectors (e.g., an optical detector as described elsewhere herein), and housings (e.g., a housing as described elsewhere herein). In some embodiments, like the embodiment shown in FIG. 7, an optical multiplexer is positioned optically between a light source system and a location configured to receive a probe and optically between a light source system and an optical detector. In such embodiments, the optical multiplexer may be positioned optically between one or more components of the light source system (e.g., one or a plurality of light-emitting diodes, a spectral broadener, a light diffuser) and a location configured to receive a probe and optically between one or more components of the light source system and an optical detector.

[0121] Optical multiplexers may be configured to divide light into two or more portions and / or may be capable of dividing light into two or more portions. For instance, in some embodiments, an optical multiplexer is configured to divide light into a first portion and a second portion and / or is capable of diving light into a first portion and a second portion. Light divided by an optical multiplexer into two or more portions may be divided such that the portions comprise light having the same wavelength range and / or such that the intensity of light at various wavelengths is the same in the portions. In some embodiments, an optical multiplexer is configured to divide light and / or is capable of dividing light into portions that are spatially separated but otherwise identical.

[0122] 14

[0123] #14430292vl Light that is divided into two or more portions by an optical multiplexer may be supplied to the optical multiplexer from a variety of suitable locations. In some embodiments, light is supplied to an optical multiplexer by a light source system described herein.

[0124] Optical multiplexers may supply portions of light to a variety of suitable locations in the instruments described herein. In some embodiments, two or more portions of light divided by the optical multiplexer may be supplied to different locations in the instrument. In some embodiments, the two or more portions of light divided by the optical multiplexer may be supplied to such locations along pathways that do not intersect. As one example of a first location to which a portion of light may be supplied, an optical multiplexer may be configured to supply and / or may be capable of supplying one of the portions to a location at which light impinges on a material in a manner that results in the generation of an optical signal, a location at which a probe is positioned, and / or a location configured to receive a probe. As one example of a second location to which a portion of light may be supplied, an optical multiplexer may be configured to supply and / or may be capable of supplying one of the portions to an optical detector. In some embodiments, an optical multiplexer is configured to supply and / or is capable of supplying a first portion of light to a first location as described in this paragraph and is configured to supply and / or is capable of supplying a second portion of light to a second location as described in this paragraph. The second portion of the light may be configured to be and / or capable of being supplied to the second location along a pathway that does not pass through the first location.

[0125] In some embodiments, an instrument described herein comprises an optical multiplexer that is configured to supply and / or is capable of supplying a first portion of light to a first location and a second portion of light to a second location (e.g., along a pathway that does not pass through the first location), and the instrument is also configured to supply and / or capable of supplying light from the first location to the second location (e.g., along a pathway that does not intersect the pathway through which the second portion of light is configured to be and / or capable of being supplied to the second location). When the second location is an optical detector, this may allow an optical detector to both receive light from a light source system (e.g., directly via a cable and / or without passing through any instrument component expected to yield an optical signal indicative of a sample being analyzed by the instrument) and receive an optical signal generated by the interaction of light with a material at the first location (e.g., with a probe,

[0126] 15

[0127] #14430292vl with a sample proximal to a probe). The light received from the light source system may be compared with the optical signal and may be employed to normalize variations in the optical signal arising from variations in the light supplied by the light source system.

[0128] Portions of light divided by an optical multiplexer may have unequal intensities. For instance, an optical multiplexer may divide light such that a relatively large percentage of it is supplied to a first location (e.g., a location at which light impinges on a material in a manner that results in the generation of an optical signal, a location at which a probe is positioned, and / or a location configured to receive a probe) and a relatively small percentage is supplied to a second location (e.g., an optical detector).

[0129] Some embodiments described herein relate to methods. Such methods may be performed by an instrument described herein and / or may be capable of being performed by an instrument described herein. Some instruments described herein may be capable of performing and / or configured to perform a method described herein.

[0130] One non-limiting example of a method is shown in FIG. 8. The method 820 shown in FIG. 8 comprises the steps 822-834. It should be noted that, although the steps in FIG. 8 are shown in one order, such steps may be performed in the order shown in FIG. 8 or in another order. It should also be noted that the steps shown in FIG. 8 may be performed for periods of time that are overlapping (partially or fully) or non-overlapping. Some methods may comprise performing some or all of the steps shown in FIG. 8 in addition to further steps not shown in FIG. 8.

[0131] The first step 828 shown in FIG. 8 is the step 822, which comprises emitting light from a light-emitting diode over a first wavelength range. The first wavelength range may be a characteristic wavelength range for the light-emitting diode. In some embodiments, the first wavelength range is relatively narrow and / or a relatively high proportion of the light emitted by the light-emitting diode is within a relatively narrow wavelength range. It should also be noted that some methods may comprise emitting light from a plurality of light-emitting diodes comprising the light-emitting diode described in the step 822.

[0132] The second step shown in FIG. 8 is the step 824, which comprises impinging the light emitted from the light-emitting diode on a spectral broadener. None, some, or all of this light may be absorbed. Light not absorbed by the spectral broadener may be transmitted therethrough. The spectral broadener may comprise a material that undergoes stimulated emission of light

[0133] 16

[0134] #14430292vl upon exposure to one or more wavelengths in the first wavelength range. It is also for the spectral broadener to otherwise broaden the wavelength range of the light impinging thereon as described elsewhere herein.

[0135] In some such embodiments, absorption of light emitted by the light-emitting diode in the step 822 may stimulate the emission of light by the spectral broadener over a second wavelength range. The emission of such light is shown in the third step 826 depicted in FIG. 8, which is an optional step. In some embodiments, the second wavelength range is not identical to the first wavelength range. In other words, the wavelength range of the light emitted by the spectral broadener may differ from the wavelength range of the light emitted by the light-emitting diode (e.g., it may comprise a wavelength that is outside the first wavelength range and / or lack one or more wavelengths present in the first wavelength range). In such embodiments, such ranges may be overlapping or non-overlapping. In some embodiments, the second wavelength range is broader than the first wavelength range and / or may fully encompass the first wavelength range. Advantageously, the emission of light over a second, different wavelength range by the spectral broadener may allow for a broader wavelength range to be emitted by the spectral broadener and the light-emitting diode together than the range emitted by the light-emitting diode alone.

[0136] The fourth step shown in FIG. 8 is the step 828, which is an optional step, and which comprises supplying light emitted from the spectral broadener to a probe. This may be accomplished in a variety of suitable manners, such as via an optically transmissive component (e.g., a cable).

[0137] The fifth step shown in FIG. 8 is the optional step 830, which comprises generating an optical signal. Optical signal generation may be performed in a variety of suitable manners as described in further detail elsewhere herein. In some embodiments, an optical signal comprises light and / or the absence of light.

[0138] The sixth step shown in FIG. 8 is the optional step 832, which comprises supplying the optical signal to an optical detector. This may be accomplished in a variety of suitable manners, such as via an optically transmissive component (e.g., a cable).

[0139] The seventh step shown in FIG. 9 is the optional step 834, which comprises detecting the optical signal. The optical signal may be detected by the optical detector to which the optical signal was supplied. Detecting the optical signal may comprise detecting the intensity of the optical signal and / or the intensity of one or more wavelengths present in the optical signal.

[0140] 17

[0141] #14430292vl Detection may be performed as a function of time and / or may comprise detecting the average of one or more properties of the optical signal over a period of time.

[0142] A second non-limiting example of a method is shown in FIGs. 9A-9B. The method 936 shown in FIG. 9 comprises the steps 938-960. It should be noted that, although the steps in FIG. 9 are shown in one order, such steps may be performed in the order shown in FIG. 9 or in another order. It should also be noted that the steps shown in FIG. 9 may be performed for periods of time that are overlapping (partially or fully) or non-overlapping. Some methods may comprise performing some or all of the steps shown in FIG. 9 in addition to further steps not shown in FIG. 9, such as one or more of the steps shown in FIG. 8.

[0143] The first step shown in FIG. 9 A is the step 938, which comprises emitting light from a light source system. The light source system may comprise one or more light-emitting diodes and / or a spectral broadener as described herein. In some embodiments, light emitted from a light source system comprises light emitted by a light-emitting diode present in the light source system and / or light emitted by a spectral broadener present in the light source system.

[0144] The second step shown in FIG. 9A is the step 940, which comprises dividing the light emitted from the light source system into first and second portions. This division may be performed by an optical multiplexer as described elsewhere herein.

[0145] The third step shown in FIG. 9A is the step 942, which comprises supplying the first portion of the light to a probe. This may be accomplished in a variety of suitable manners, such as via an optically transmissive component (e.g., a cable).

[0146] The fourth step shown in FIG. 9A is the optional step 944, which comprises generating an optical signal from the portion of the light. Optical signal generation may be performed in a variety of suitable manners as described in further detail elsewhere herein. In some embodiments, an optical signal comprises light and / or the absence of light.

[0147] The fifth step shown in FIG. 9A is the optional step 946, which comprises supplying the optical signal to an optical detector. This may be accomplished in a variety of suitable manners, such as via an optically transmissive component (e.g., a cable).

[0148] The sixth step shown in FIG. 9A is the optional step 948, which comprises detecting the optical signal. The optical signal may be detected by the optical detector to which the optical signal was supplied. Detecting the optical signal may comprise measuring the intensity of the optical signal and / or the intensity of one or more wavelengths present in the optical signal.

[0149] 18

[0150] #14430292vl Detection may be performed as a function of time and / or may comprise detecting the average of one or more properties of the optical signal over a period of time.

[0151] The seventh step shown in FIG. 9A is the step 950, which comprises supplying the second portion of the light to an optical detector. This may be accomplished in a variety of suitable manners, such as via an optically transmissive component (e.g., a cable). The optical detector may be the same optical detector to which the optical signal is supplied in the optional step 946, or it may be a different optical detector.

[0152] In some embodiments, a second portion of light may be supplied to an optical detector along a pathway that does not pass through the probe. This may be desirable because it may allow for such light to not be employed in the generation of an optical signal and / or to be separated spatially and / or in time from light employed in the generation of an optical signal. Such separation may allow for the second portion of light to undergo relatively few spectral and / or intensity changes after being emitted from the light source system and being detected by the optical detector, which may advantageously allow for it to be employed as an internal standard that provides relatively accurate information regarding the light emitted from the light source system.

[0153] The last step shown in FIG. 9A is the optional step 952, which comprises performing one or more of the further steps shown in FIG. 9B. Similarly, the first step shown in FIG. 9B is the step 954 of performing one or more of the steps shown in FIG. 9A.

[0154] The second step shown in FIG. 9B is the optional step 956, which comprises detecting the second portion of light. This portion of light may be detected by the optical detector to which it was supplied (e.g., the same optical detector employed to detect an optical signal in the optional step 946 or a different optical detector). Detecting the second portion of light may comprise measuring the intensity of the second portion of light and / or the intensity of one or more wavelengths present in the second portion of light. Detection may be performed as a function of time and / or may comprise detecting the average of one or more properties of the second portion of light over a period of time.

[0155] The third step shown in FIG. 9B is the optional step 958, which comprises determining whether the light emitted from the light source system varies with time. This may be performed by determining whether the light detected in the optional step 956 has an intensity that varies as a function of time and / or whether any of the wavelengths present in such light has an intensity that

[0156] 19

[0157] #14430292vl varies as a function of time. This may be accomplished manually (e.g., by having an operator observe the intensity of the light and / or wavelengths therein as a function of time) and / or automatically (e.g., with the use of a computer).

[0158] The fourth step shown in FIG. 9B is the optional step 960, which comprises normalizing a measured intensity of the optical signal by a measured intensity of the second portion of the light. This normalization may be performed as a function of wavelength and / or on an average intensity across all measured wavelengths. Similarly, this normalization may be performed on average intensities and / or as a function of time. The normalization may be accomplished manually (e.g., by having an operator perform the relevant math) and / or automatically (e.g., with the use of a computer).

[0159] The final step shown in FIG. 9B is the optional step 962, which comprises adjusting the intensity of the light emitted from the light source system. This may be performed if it is determined that the light emitted by the light source system varies with time (e.g., as in the step 958) or if it is determined that a different intensity would enhance optical signal generation and / or reduce noise. The intensity of the light emitted from the light source system may be adjusted by adjusting the amount of current supplied to light-emitting diodes therein. This may be performed by use of an electrical controller and / or manually.

[0160] The light-emitting diodes described herein may have a variety of suitable compositions. Non-limiting examples of such compositions include gallium arsenide, gallium nitride, indium gallium nitride, and gallium phosphide. Without wishing to be bound by any particular theory, it is believed that light-emitting diodes comprising gallium arsenide may be particularly suitable for emitting infrared light, light-emitting diodes comprising gallium nitride may be particularly suitable for emitting ultraviolet light, and light-emitting diodes comprising indium gallium nitride may be particularly suitable for emitting green light, blue light, and / or ultraviolet light. It is believed that such light-emitting diodes may exhibit desirable stability and / or longevity. It is also believed that light-emitting diodes comprising gallium nitride may exhibit desirable brightness, and that light-emitting diodes comprising indium gallium nitride may exhibit desirable efficiencies.

[0161] The light-emitting diodes described herein may emit light over a variety of suitable wavelength ranges. In some embodiments, a light source system comprises a light-emitting diode that is configured to emit light having a wavelength of greater than or equal to 190 nm,

[0162] 20

[0163] #14430292vl greater than or equal to 200 nm, greater than or equal to 250 nm, greater than or equal to 300 nm, greater than or equal to 350 nm, greater than or equal to 400 nm, greater than or equal to 450 nm, greater than or equal to 500 nm, greater than or equal to 550 nm, greater than or equal to 600 nm, greater than or equal to 650 nm, greater than or equal to 700 nm, greater than or equal to 750 nm, greater than or equal to 800 nm, greater than or equal to 850 nm, greater than or equal to 900 nm, greater than or equal to 950 nm, greater than or equal to 1000 nm, greater than or equal to 1050 nm, greater than or equal to 1100 nm, or greater than or equal to 1150 nm. In some embodiments, a light source system comprises a light-emitting diode that is configured to emit light having a wavelength of less than or equal to 1200 nm, less than or equal to 1150 nm, less than or equal to 1100 nm, less than or equal to 1050 nm, less than or equal to 1000 nm, less than or equal to 950 nm, less than or equal to 900 nm, less than or equal to 850 nm, less than or equal to 800 nm, less than or equal to 750 nm, less than or equal to 700 nm, less than or equal to 650 nm, less than or equal to 600 nm, less than or equal to 550 nm, less than or equal to 500 nm, less than or equal to 450 nm, less than or equal to 400 nm, less than or equal to 350 nm, less than or equal to 300 nm, less than or equal to 250 nm, or less than or equal to 190 nm. Combinations of the above-referenced ranges are also possible (e.g., greater than or equal to 190 nm and less than or equal to 1200 nm).

[0164] When a light source system comprises more than one light-emitting diode, each light emitting diode may independently be configured to emit light having a wavelength in one or more of the above-referenced ranges.

[0165] Without wishing to be bound by any particular theory, it is believed that ultraviolet light may be particularly suitable for detecting specific protein interactions and / or for detecting an optical signal with relatively high resolution and / or sensitivity. It is also believed that infrared light may be particularly suitable for penetrating biological samples effectively while still providing adequate sensitivity.

[0166] As noted above, some light source systems described herein comprise a spectral broadener. A spectral broadener may broaden the wavelength range of light impinging thereon and / or may emit light having a wavelength range that does not completely overlap with the wavelength range of light impinging thereon. A variety of suitable spectral broadeners may be employed in the light source systems described herein. Non-limiting examples of suitable spectral broadeners include photonic crystals, dispersive optical elements (e.g., diffraction

[0167] 21

[0168] #14430292vl gratings), nonlinear optical materials (e.g., those exhibiting second-harmonic generation), and wavelength converters (e.g., phosphors, such as phosphor coatings). Photonic crystals may serve to broaden the wavelength range of light impinging thereon by manipulating the propagation of light therethrough by periodic structures therein. Dispersive optical elements may serve to broaden the wavelength range of light impinging thereon by separating light into its constituent wavelengths. Nonlinear optical materials may serve to broaden the wavelength range of light impinging thereon by interacting with such light to produce new frequencies.

[0169] Some spectral broadeners, such as wavelength converters, may be configured to absorb light having a wavelength in a range emitted by a light-emitting diode also positioned in the instrument. Such spectral broadeners may be further configured to emit light over a second wavelength range (e.g., upon such absorption). In some embodiments, a spectral broadener is configured such that absorption of light having a wavelength in a range emitted by the lightemitting diode stimulates the emission of light from the spectral broadener. Light may be emitted from the spectral broadener (e.g., upon absorption of light emitted by a light-emitting diode) via luminescence and / or phosphorescence.

[0170] It is also possible for a spectral broadener to be stimulated to emit light (e.g., over a second wavelength range) by a process other than the absorption of light emitted by a lightemitting diode, such as via the absorption of ambient light and / or the absorption of thermal energy.

[0171] The wavelength range over which a spectral broadener may emit light may be selected as desired. In some embodiments, a wavelength range over which a spectral broadener emits light comprises wavelengths of greater than or equal to 190 nm, greater than or equal to 200 nm, greater than or equal to 250 nm, greater than or equal to 300 nm, greater than or equal to 350 nm, greater than or equal to 400 nm, greater than or equal to 450 nm, greater than or equal to 500 nm, greater than or equal to 550 nm, greater than or equal to 600 nm, greater than or equal to 650 nm, greater than or equal to 700 nm, greater than or equal to 750 nm, greater than or equal to 800 nm, greater than or equal to 850 nm, greater than or equal to 900 nm, greater than or equal to 950 nm, greater than or equal to 1000 nm, greater than or equal to 1050 nm, greater than or equal to 1100 nm, or greater than or equal to 1150 nm. In some embodiments, a wavelength range over which a spectral broadener emits light comprises wavelengths of less than or equal to 1200 nm, less than or equal to 1150 nm, less than or equal to 1100 nm, less than or equal to 1050 nm, less than

[0172] 22

[0173] #14430292vl or equal to 1000 nm, less than or equal to 950 nm, less than or equal to 900 nm, less than or equal to 850 nm, less than or equal to 800 nm, less than or equal to 750 nm, less than or equal to 700 nm, less than or equal to 650 nm, less than or equal to 600 nm, less than or equal to 550 nm, less than or equal to 500 nm, less than or equal to 450 nm, less than or equal to 400 nm, less than or equal to 350 nm, less than or equal to 300 nm, less than or equal to 250 nm, or less than or equal to 190 nm. In some embodiments, a spectral broadener emits light over a wavelength range that extends between two or more of the wavelengths described above (e.g., over a wavelength range that extends from 190 nm to 1200 nm). It is also possible for a spectral broadener to emit light comprising wavelengths other than those provided above.

[0174] The width of the wavelength range over which a spectral broadener may emit light may be selected as desired. In some embodiments, a wavelength range over which a spectral broadener emits light has a width of greater than or equal to 190 nm, greater than or equal to 200 nm, greater than or equal to 250 nm, greater than or equal to 300 nm, greater than or equal to 350 nm, greater than or equal to 400 nm, greater than or equal to 450 nm, greater than or equal to 500 nm, greater than or equal to 550 nm, greater than or equal to 600 nm, greater than or equal to 650 nm, greater than or equal to 700 nm, greater than or equal to 750 nm, greater than or equal to 800 nm, greater than or equal to 850 nm, greater than or equal to 900 nm, greater than or equal to 950 nm, greater than or equal to 1000 nm, greater than or equal to 1050 nm, greater than or equal to 1100 nm, or greater than or equal to 1150 nm. In some embodiments, a wavelength range over which a spectral broadener emits light has a width of less than or equal to 1200 nm, less than or equal to 1150 nm, less than or equal to 1100 nm, less than or equal to 1050 nm, less than or equal to 1000 nm, less than or equal to 950 nm, less than or equal to 900 nm, less than or equal to 850 nm, less than or equal to 800 nm, less than or equal to 750 nm, less than or equal to 700 nm, less than or equal to 650 nm, less than or equal to 600 nm, less than or equal to 550 nm, less than or equal to 500 nm, less than or equal to 450 nm, less than or equal to 400 nm, less than or equal to 350 nm, less than or equal to 300 nm, less than or equal to 250 nm, less than or equal to 200 nm, or less than or equal to 190 nm. Combinations of the above- referenced ranges are also possible (e.g., greater than or equal to 190 nm and less than or equal to 1200 nm). Other ranges are also possible.

[0175] As noted above, some light source systems described herein comprise a temperature controller. The temperature controller may control the temperature of one or more components

[0176] 23

[0177] #14430292vl of the light source system. The temperature controller may be configured to maintain and / or may be capable of maintaining the temperature of one or more components of a light source system (e.g., a light-emitting diode, a plurality of light-emitting diodes, a spectral broadener) at a relatively constant temperature. In some embodiments, one temperature controller may be configured to maintain and / or may be capable of maintaining the temperature of two or more components at the same temperature. It is also possible for one temperature controller to be configured to maintain and / or may be capable of maintaining the temperature of two or more components at different temperatures. As yet a third possibility, a light source system may comprise two or more temperature controllers, each configured to maintain and / or capable of maintaining one or more components of a light source system at a relatively constant temperature. It is also possible for an instrument described herein to comprise a temperature controller that controls the temperature of one or more components of the instrument not present in a light source system (e.g., an optical detector). Such temperature controller(s) may be configured to maintain and / or be capable of maintaining the temperature of such a component at a relatively constant temperature.

[0178] Temperature controllers may maintain the temperature of light source system components in a variety of suitable manners. In some embodiments, a temperature controller comprises one or more fans and / or sources of air that may be capable of directing and / or configured to pass air having a particular temperature across the light source system component whose temperature is being controlled. In some embodiments, a temperature controller comprises a Peltier element, a heat pump, and / or a heat sink, and / or a thermoelectric cooler.

[0179] In some embodiments, a light source system comprises a temperature controller that is configured to maintain and / or is capable of maintaining the temperature of a light-emitting diode such that it varies by no more than 1 °C, no more than 0.75 °C, no more than 0.5 °C, no more than 0.2 °C, no more than 0.1 °C, no more than 0.075 °C, no more than 0.05 °C, or no more than 0.02 °C. In some embodiments, a light source system comprises a temperature controller that is configured to maintain and / or is capable of maintaining the temperature of a light-emitting diode such that it varies by greater than or equal to 0.01 °C, greater than or equal to 0.02 °C, greater than or equal to 0.05 °C, greater than or equal to 0.075 °C, greater than or equal to 0.1 °C, greater than or equal to 0.2 °C, greater than or equal to 0.5 °C, or greater than or equal to 0.75 °C. Combinations of the above-referenced ranges are also possible (e.g., no more than 1 °C and

[0180] 24

[0181] #14430292vl greater than or equal to 0.01 °C). Other ranges are also possible. Some methods comprise performing one or more steps (e.g., one or more steps shown in FIG. 8 and / or FIG. 9) while the temperature of a light-emitting diode is controlled such that it varies by an amount in one or more of the above-referenced ranges.

[0182] In some embodiments, a light source system comprises a temperature controller that is configured to maintain and / or is capable of maintaining the temperature of a spectral broadener such that it varies by no more than 1 °C, no more than 0.75 °C, no more than 0.5 °C, no more than 0.2 °C, no more than 0.1 °C, no more than 0.075 °C, no more than 0.05 °C, or no more than 0.02 °C. In some embodiments, a light source system comprises a temperature controller that is configured to maintain and / or is capable of maintaining the temperature of a spectral broadener such that it varies by greater than or equal to 0.01 °C, greater than or equal to 0.02 °C, greater than or equal to 0.05 °C, greater than or equal to 0.075 °C, greater than or equal to 0.1 °C, greater than or equal to 0.2 °C, greater than or equal to 0.5 °C, or greater than or equal to 0.75 °C. Combinations of the above-referenced ranges are also possible (e.g., no more than 1 °C and greater than or equal to 0.01 °C). Other ranges are also possible. Some methods comprise performing one or more steps (e.g., one or more steps shown in FIG. 8 and / or FIG. 9) while the temperature of a spectral broadener is controlled such that it varies by an amount in one or more of the above-referenced ranges.

[0183] In some embodiments, an instrument described herein comprises two or more components that are thermally insulated from each other. Components that are thermally insulated from each other may be separated from each other by one or more thermally insulative materials. In some embodiments, such components are thermally insulated from each other such that they are capable of being maintained at different temperatures by different temperature controllers. Non-limiting examples of components that may be thermally insulated from each other include a light-emitting diode that is thermally insulated from an optical detector, a lightemitting diode that is thermally insulated from a spectral broadener, and a spectral broadener that is thermally insulated from an optical detector.

[0184] As noted above, some light source systems described herein comprise a light diffuser. Light diffusers may be capable of mixing and / or configured to mix light, such as light received from a plurality of light-emitting diodes. Light diffusers may be positioned optically between two or more light sources (e.g., two or more light-emitting diodes) and a location and / or

[0185] 25

[0186] #14430292vl component to which light therefrom is to be supplied (e.g., a spectral broadener, a probe, a location configured to receive a probe). Such light diffusers may be capable of mixing and / or configured to mix the light received from the light sources prior to its impingement on the relevant component and / or location, which may facilitate the impingement thereon of light that is spatially uniform (e.g., across the cross-section of the light perpendicular to the direction of its propagation).

[0187] One non-limiting example of a suitable light diffuser is a light pipe. The light pipe may be transparent to light. In some embodiments, a light pipe has a design such that light entering thereinto under a wide variety of angles undergoes total internal reflection while being transmitted therethrough. For instance, the light pipe may be formed from a material that has a relatively high refractive index and / or that has a geometry with respect to the light entering thereinto that promotes the impingement of light on its external surfaces at angles that result in total internal reflection. Light entering the light diffuser at different angles may traverse optical paths having different lengths and / or may be spatially mixed by the total internal reflection. This is shown schematically in FIGs. 10 and 11, the former of which depicts an incident beam of light being transmitted through a light pipe with a hexagonal cross-section and the latter of which depicts total internal reflection along the length of an exemplary light pipe.

[0188] In some embodiments, a light pipe is a hexagonal rod, like the hexagonal rod shown in FIG. 10.

[0189] Another non-limiting example of a suitable light diffuser is a holographic diffuser. A holographic diffuser may comprise an interference pattern between two light beams that is recorded therein and then developed to result in a surface comprising microstructures that act as diffraction gratings. Light incident on a transmissive holographic diffuser may be transmitted through the holographic diffuser and scattered by the microstructures, which may spatially mix the light.

[0190] As described above, light source systems and instruments described herein may be capable of supplying and / or configured to supply light from some locations to other locations. Similarly, some methods comprise supplying light from one location to another. Light may be supplied from one location to another by passing through an optically transmissive component and / or material positioned optically between these two locations.

[0191] 26

[0192] #14430292vl In some embodiments, a light source system and / or an instrument comprises one or more cables, such as one or more optical cables. Such cables may be capable of supplying, configured to supply, and / or employed to supply light from one location to another. For instance, an instrument may comprise a cable that is capable of supplying, configured to supply, and / or employed to supply light from a light source system (e.g., from a spectral broadener therein, from a light diffuser therein) to a location configured to receive a probe, from a light source system to a probe, from a light source system to an optical multiplexer, from an optical multiplexer to an optical detector, and / or from a probe to an optical detector. Light transmitted from a probe via a cable may comprise light that has been transmitted through the probe (e.g., it may comprise an optical signal transmitted through the probe).

[0193] A variety of suitable cables may be present in the instruments described therein. Some cables may comprise two or more fibers. In some embodiments, a cable comprises a fiber-optic bundle and / or is a fiber-optic cable. Cables comprising fiber-optic bundles may comprise one or more optical fibers forming a core and a cladding surrounding the core.

[0194] In some embodiments, a cable may comprise a fiber bundle, such as a fiber-optic bundle and / or a furcated fiber bundle. Fiber bundles may comprise a plurality of fibers. When present, fibers in a cable may be single mode or multimode. In some embodiments, a cable comprises one or more apertures through which light may be transmitted. For instance, a cable may comprise a plurality of fibers and / or optical fibers, and the terminus of each optical fiber may serve as an aperture through which light may be transmitted. When present, the apertures may be positioned on a side of the cable opposite a side on which any optical detectors and / or light source systems are positioned. In such embodiments, the cable may serve to transmit light from a light source system to an aperture and / or to transmit light from an aperture to an optical detector described herein.

[0195] The cables described herein may comprise fibers (e.g., optical fibers) having a variety of suitable diameters. In some embodiments, a cable comprises a fiber (e.g., an optical fiber) having a core with a diameter of greater than or equal to 150 microns, greater than or equal to 200 microns, greater than or equal to 300 microns, greater than or equal to 400 microns, greater than or equal to 500 microns, greater than or equal to 600 microns, greater than or equal to 700 microns, greater than or equal to 800 microns, greater than or equal to 900 microns, greater than or equal to 1000 microns, greater than or equal to 1100 microns, greater than or equal to 1200

[0196] 27

[0197] #14430292vl microns, greater than or equal to 1300 microns, greater than or equal to 1400 microns, greater than or equal to 1500 microns, greater than or equal to 1600 microns, greater than or equal to 1700 microns, greater than or equal to 1800 microns, or greater than or equal to 1900 microns. In some embodiments, a cable comprises a fiber (e.g., an optical fiber) having a core with a diameter of less than or equal to 2000 microns, less than or equal to 1900 microns, less than or equal to 1800 microns, less than or equal to 1700 microns, less than or equal to 1600 microns, less than or equal to 1500 microns, less than or equal to 1400 microns, less than or equal to 1300 microns, less than or equal to 1200 microns, less than or equal to 1100 microns, less than or equal to 1000 microns, less than or equal to 900 microns, less than or equal to 800 microns, less than or equal to 700 microns, less than or equal to 600 microns, less than or equal to 500 microns, less than or equal to 400 microns, less than or equal to 300 microns, or less than or equal to 200 microns. Combinations of the above-referenced ranges are also possible (e.g., greater than or equal to 150 microns and less than or equal to 2000 microns, or greater than or equal to 400 microns and less than or equal to 2000 microns). Other ranges are also possible.

[0198] The cables described herein may comprise a variety of suitable amounts of fibers and / or optical fibers. In some embodiments, a cable comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or more fibers and / or optical fibers.

[0199] In some embodiments, an instrument described herein further comprises one or more components that assist with supplying light to a cable. For instance, a light source system may comprise one or more components that enhance the percentage of the light emitted by the light source system that is supplied to the cable. FIGs. 12-14 show three different examples of how light may be supplied from a light source system (denoted as “LED” in these Figures) to a cable (denoted as “BLI fiber bundle” in these Figures). FIG. 12 shows the supply of light directly to a cable from a light source system, FIG. 13 shows the supply of light to a cable that interacts with one component after being emitted from the light source system and before impinging on the cable, and FIG. 14 shows the supply of light to a cable that interacts with two components after being emitted from the light source system and before impinging on the cable.

[0200] As one example, in some embodiments, an instrument comprises a focusing element positioned optically between a light source system and a cable (e.g., a cable configured to supply and / or capable of supplying light from the light source system to a location configured to receive a probe, from a light source system to a probe, and / or from a light source system to an optical

[0201] 28

[0202] #14430292vl multiplexer). It is also possible for an instrument to comprise two or more such focusing elements (e.g., both positioned optically between a light source system and a cable). In some embodiments, an instrument comprises one or more such focusing elements that are transmissive, such as one or more lenses.

[0203] As another example, in some embodiments, an instrument further comprises a reflective element positioned optically between a light source system and a cable (e.g., a cable configured to supply and / or capable of supplying light from the light source system to a location configured to receive a probe, from a light source system to a probe, and / or from a light source system to an optical multiplexer). It is also possible for an instrument to comprise two or more such reflective elements (e.g., both positioned optically between a light source system and a cable). One nonlimiting example of a suitable reflective element is a mirror.

[0204] As noted above, in some embodiments, a light source system and / or instrument described herein is capable of operating and / or configured to operate in conjunction with a probe. Similarly, a method described herein may comprise transmitting light through a probe. The probe may receive light from a light source system (e.g., via a cable). In some embodiments, a probe has one or more features that facilitate the generation of an optical signal and / or detection of an optical signal. For instance, a probe may be capable of transmitting and / or configured to transmit light from a light source (e.g., via a cable placing the light source in optical communication with the probe) through the probe and / or to the end of the probe. As another example, a probe may be capable of transmitting and / or configured to transmit light (e.g., light reflected from an interface internal to the probe, light reflected from the end of the probe) through the probe and to an optical detector (e.g., via a cable placing the probe in optical communication with the optical detector). As a third example, a probe may comprise one or more features (e.g., one or more structural features) that assist with generating an optical signal.

[0205] The probes described herein may have a variety of suitable designs. Some probes described herein are optical probes. Such probes may be part of one or more optical pathways present in an instrument described herein (e.g., between a light source system and an environment external to the probe) and / or may be configured to transmit light. In some embodiments, a probe is transparent to and / or may transmit light at a plurality of wavelengths (e.g., visible wavelengths, infrared wavelengths, near infrared wavelengths, wavelengths of light emitted by a light source system, wavelengths of light that an optical detector is capable of

[0206] 29

[0207] #14430292vl detecting and / or configured to detect). Some probes comprise one or more polished ends to facilitate transmission. Such polished ends may be perpendicular to the optical axis of the probe.

[0208] In some embodiments, a probe is a fiber-optic probe and / or comprises one or more fibers, such as one or more optical fibers. Such optical fibers may have one or more features of the optical fibers suitable for inclusion in cables described elsewhere herein.

[0209] It is also possible for a probe (and / or a fiber therein) to be in optical communication (or be configured to be and / or capable of being in such optical communication) with one or more fiber-optic cables and / or cables comprising two or more fibers. Such cables may transmit light from a light source system to a probe (and / or a fiber therein) and / or from a probe (and / or a fiber therein) to an optical detector. This may be accomplished when at least one of the fibers in the cable is in optical communication with an optical fiber present in the probe. In such embodiments, it is also possible for the cable to comprise two or more fibers in optical communication with the optical fiber present in the probe and / or to comprise one or more further fibers not in optical communication with the optical fiber present in the probe. The latter fibers may transmit light from a light source system to an optical detector that does not pass through the probe and / or transmit one or more other types of reference signals.

[0210] It is also possible for a probe to comprise further optics (e.g., in addition to fibers and / or optical fibers) that assist with the transmission of light. As an example, a probe may comprise a lens and / or a pinhole. When present, these components may assist with near-field imaging. In some embodiments, a probe comprises a transmissive collimator that is configured to collect and transmit light to the probe and / or a component thereof. As an example, the transmissive collimator may be configured to collect and transmit light to an axis along the center and / or optical axis of the probe, along the center and / or optical axis of an optical fiber present in the probe, and / or along the center and / or optical axis of a bundle (e.g., a fiberoptic bundle) present in the probe.

[0211] In some embodiments, a probe comprises one or more components that allow it to be optically coupled to a light source system, an optical detector as described herein, and / or a component thereof (e.g., a spectral broadener). As an example, in some embodiments, a probe comprises a component, such as a plastic hub, that is compatible with an SMA connector (e.g., an SMA905 connector), a BNC connector, a connector with push, lock, and / or twist functionality, and / or a compression spring. In some embodiments, a probe is coupled to a cable

[0212] 30

[0213] #14430292vl via a ferrule. The ferrule may comprise optical fibers comprising polished tips, which may facilitate optical communication with the probe. In some embodiments, a probe is capable of being and / or configured to be optically coupled to a cable that comprises one or more components to assist with strain relief at the location of the coupling.

[0214] In some embodiments, a probe (and / or one or more fibers present in a probe) comprises an interface internal thereto. As described above, such probes may be particularly suitable for generating optical signals comprising an amount of light that has been reflected from this interface and an amount of type of light that has been reflected from the end of the probe. When present, such interfaces may extend across the entirety of a probe and / or fiber cross-section (e.g., the cross-section perpendicular to the axis along which light is transmitted through the probe, the cross-section perpendicular to the long axis of the probe). Interfaces internal to probes and / or fibers may have a variety of suitable designs. In some embodiments, a probe and / or fiber comprises an internal interface that takes the form of an interface between an interior portion of the probe and / or fiber and a coating disposed on the interior portion of the probe and / or fiber. FIG. 15 shows one non-limiting embodiment of a probe having such a design. The probe 1564 shown in FIG. 15 includes an internal interface 1566 between the interior portion of the probe 1568 and the coating 1570 disposed on the interior portion of the probe.

[0215] In some embodiments, a probe comprises a coating disposed on an interior portion of the probe and one or more further portions of the probe disposed on the coating. As one example, in some embodiments, a probe further comprises a second coating disposed on the coating disposed on the interior portion of the probe. The second coating may be formed from the same material as the interior portion of the probe. FIG. 16 shows one example of such a probe. In FIG. 16, the probe 1664 includes a second coating 1672 disposed on the coating 1670. This probe also includes an internal interface 1666 between the interior portion of the probe 1668 and the coating 1670. As another example, in some embodiments, one or more species are immobilized on the probe (not shown), such as on the end of the probe.

[0216] Probes, internal interfaces thereto, and coatings may have a variety of suitable shapes. For instance, a probe, an internal interface, and / or a coating may have a hexagonal and / or a round cross-section.

[0217] The various components of the probes described herein may have a variety of suitable compositions. In some embodiments, one or more portions of a probe and / or fiber (e.g., an

[0218] 31

[0219] #14430292vl interior portion, a coating, a second coating disposed on a coating disposed on an interior portion, the entirety of the probe) comprises a glass. Non-limiting examples of suitable glasses include SiCh and Ta2Os. In some embodiments, a probe comprises an interior portion and / or a second coating comprising SiCh and a coating comprising Ta2Os. In some embodiments, one or more portions of a probe and / or fiber (e.g., an interior portion, a coating, a second coating disposed on a coating disposed on an interior portion, the entirety of the probe) comprises a polymer. Non-limiting examples of suitable polymers include polystyrene and polyethylene.

[0220] The coatings described herein may have a variety of suitable thicknesses. In some embodiments, one or both of the coatings (and / or both coatings together) have a thickness of greater than or equal to 50 nm, greater than or equal to 100 nm, greater than or equal to 200 nm, greater than or equal to 500 nm, greater than or equal to 750 nm, greater than or equal to 1 micron, greater than or equal to 2 microns, greater than or equal to 3 microns, or greater than or equal to 4 microns. In some embodiments, one or both of the coatings (and / or both coatings together) have a thickness of less than or equal to 5 microns, less than or equal to 4 microns, less than or equal to 3 microns, less than or equal to 2 microns, less than or equal to 1 micron, less than or equal to 750 nm, less than or equal to 500 nm, less than or equal to 200 nm, or less than or equal to 100 nm. Combinations of the above-referenced ranges are also possible (e.g., greater than or equal to 50 nm and less than or equal to 5 microns, greater than or equal to 100 nm and less than or equal to 5 microns, or greater than or equal to 500 nm and less than or equal to 1 micron). Other ranges are also possible.

[0221] In some embodiments, a probe comprises a surface that is functionalized, that has a surface chemistry that assists with the performance of an assay, and / or has a surface chemistry that assists with the immobilization of a species thereon. The surface functionalization and / or chemistry may promote the immobilization thereon of reaction products that are typically generated during assays. For instance, the surface functionalization and / or chemistry may promote the immobilization of one or more species generated during the assay thereon. It is also possible for a surface functionalization and / or chemistry to promote the immobilization thereon of one or more species that may be present in an environment with which the probe is in contact. In some embodiments, and as described above, a probe comprises a surface on which one or more species that are reagents are immobilized. The reagent(s) may be immobilized on the probe in a variety of suitable manners. As an example, the reagent(s) may be bonded to the

[0222] 32

[0223] #14430292vl probe. The bonding may comprise covalent bonding, ionic bonding, polar bonding, van der Waals bonding, hydrophobic bonding, and / or hydrogen bonding.

[0224] A variety of suitable reagents may be immobilized on the probes described herein. Some reagents may be species that are capable of that engaging in one or more chemical reactions (e.g., one or more chemical reactions that may take place during an assay that the probe is employed to facilitate). For instance, a probe may comprise a reagent that is capable of bonding with another species (e.g., covalently, ionically, by polar interactions, by van der Waals interactions, hydrophobically, by hydrogen bonding, by complexing), absorbing another species, adsorbing another species, catalyzing a reaction of another species and / or between two or more species, decomposing (e.g., upon exposure to another species), undergoing a conformational shift, and / or catalyzing a reaction. In some embodiments, one or more of the previously described chemical reactions may cause the species with which the reagent reacts to become immobilized thereon. Selected non-limiting examples of suitable reagents include biomolecules (e.g., proteins, glycoproteins, peptides, nucleic acids (e.g., DNA, RNA, mRNA), antibodies (e.g., antibodies for exosomes, such as anti-CD63 and / or anti-CD9, antibodies for proteins, antibodies for viruses, antibodies for virus-like particles), antibody fragments, antigens, polysaccharides, carbohydrates, hormones, streptavidin, glutathione), ligands (e.g., ligands for proteins, such as protein A), small molecules, viruses, cells, inorganic compounds (e.g., aminopropylsilane), sequestration compounds, capsids, bacteria resins (e.g., Ni-NTA), plasmids, nutrient components, metabolics, metabolic byproducts, and combinations thereof. Non-limiting examples of proteins include protein A, protein G, protein L, and lectin. One non-limiting example of a combination of two or more of the previously described reagent types is a reagent that comprises protein A and an antibody to an exosome and / or a virus. The antibody may be immobilized on protein A immobilized on a probe and / or fiber surface and may be capable of immobilizing an exosome and / or a virus. In such embodiments, as well as others, two or more reagents are immobilized on a probe and / or fiber (and, in some embodiments, one or more such reagents may be a combination of two or more reagents).

[0225] In some embodiments, a species immobilized on a surface of a probe is suitable for engaging in a chemical and / or biological reaction that comprises binding. It is also possible for a probe to be suitable for engaging in a chemical and / or biological reaction that does not comprise binding. When present, binding may comprise a reaction between a target and a binding partner

[0226] 33

[0227] #14430292vl that specifically binds to the target (e.g., an agent or molecule that specifically binds to the target). Binding may also comprise immobilizing a target on the binding partner. In some embodiments, the binding partner may specifically bind to an epitope on the target molecule. Non-limiting examples of specific pairs of binding partners and targets include an antibody and an antigen, an antibody fragment and an antigen, an antibody and a hapten, an antibody and a peptide, an antibody and a small molecule, an antigen and a fusion protein, an antibody fragment and a hapten, an enzyme and an enzymatic substrate, an enzyme and an inhibitor, an enzyme and a cofactor, a binding protein and a substrate, a carrier protein and a substrate, a protein and a small molecule, lecithin and a carbohydrate, a receptor and a hormone, a receptor and an effector, complementary strands of nucleic acid, a protein in combination with a nucleic acid repressor and an inducer, a ligand and a cell surface receptor, a virus and a ligand, and a receptor and a ligand.

[0228] Non-limiting examples of antibodies that may be binding partners or antibodies include intact (i.e., full-length) polyclonal and monoclonal antibodies, antigen-binding fragments of polyclonal and monoclonal antibodies (such as Fab, Fab', F(ab')2, or Fv), single chains (scFv) mutants of single chains, fusion proteins comprising an antibody portion, humanized antibodies, chimeric antibodies, diabodies, linear antibodies, single chain antibodies, multispecific antibodies (e.g., bispecific antibodies), and modified configurations of the immunoglobulin molecule that comprise an antigen recognition site of the required specificity. Non-limiting examples of antibodies falling into the last category include glycosylation variants of antibodies, amino acid sequence variants of antibodies, and covalently modified antibodies. Additionally, a binding partner may be an antibody of any class, such as IgD, IgE, IgG, IgA, or IgM (or subclass thereof, e.g., IgGl, IgG2, IgG3, IgG4, IgAl and / or IgA2).

[0229] An antigen may be a molecule or a portion of a molecule that can have antibodies generated against it. Antigens may be peptides, polysaccharides and / or lipids. Some antigens may originate from within the body (a “self-antigen”), and some antigens may originate from the external environment (a “non-self-antigen”).

[0230] In some embodiments, antibodies suitable for performing a chemical and / or biological reaction specifically bind to epitopes on their target molecules. An epitope (which may be referred to as an antigenic determinant) may be the part of the antigen recognized (or bound by) an antibody. For example, the epitope may be the specific piece of the antigen to which an

[0231] 34

[0232] #14430292vl antibody binds. The part of an antibody that binds to the epitope may be referred to as a paratope. An epitope may be a conformational epitope (composed of discontinuous amino acids or sections of the antigen) or a linear epitope (composed of continuous amino acids). Some proteins may share segments of high sequence homology and / or structural similarity. These similar proteins may have common epitopes (in other words, the epitopes on different antibodies may be bound by the same antibody). Further, a protein that has been processed differentially (such as a protein that has gone a further enzymatic process) may share some, but not all, epitopes with its pre-processing form. Non-limiting examples of different epitopes that may be added or removed during processing include N-terminal signal peptides (as seen, for example, on pre-pro-peptides) and changes seen when an inactive protein (e.g., a pro-peptide) is turned into an active form by post-translational modification.

[0233] When an antibody specifically binds to an epitope, it may engage in a binding reaction that is capable of discriminating between a target molecule and a non-target molecule. For example, a binding partner may specifically bind to a target molecule with greater than or equal to 2-fold, with greater than or equal to 4-fold, greater than or equal to 5 -fold, greater than or equal to 6-fold, greater than or equal to 7-fold, greater than or equal to 8-fold, greater than or equal to 9-fold, greater than or equal to 10-fold, greater than or equal to 20-fold, greater than or equal to 25-fold, greater than or equal to 50-fold, or greater than or equal to 100-fold greater affinity than to a non-target molecule.

[0234] The binding affinity of an antibody may be parametrized by its affinity (KD). The KD is the ratio of the dissociation constant to the association constant (Ko=Kd / Ka). In some embodiments, a binding partner described herein has an affinity (KD) of less than or equal to 10'5M, less than or equal to 10'6M, less than or equal to 10'7M, less than or equal to 10'8M, less than or equal to 10'9M, less than or equal to IO'10M, less than or equal to 10"11M, or less than or equal to 10'12M. An increased affinity KD corresponds to a decreased dissociation constant Kd or an increased association constant (Ka). Higher affinity binding of a binding partner (e.g., an antibody) to a first molecule relative to a second molecule can be indicated by a higher Ka(or a smaller numerical value of KD and / or Ka) for binding to the first target than the Ka(or numerical value of KD and / or Ka) for binding to the second target. In such cases, the antibody has a specificity for the first molecule (e.g., a protein in a first conformation or mimic thereof) relative to the second molecule (e.g., the same protein in a second conformation or mimic thereof, or a

[0235] 35

[0236] #14430292vl second protein). Differences in binding affinity (e.g., specificity) can be greater than or equal to 1.5-fold, greater than or equal to 2-fold, greater than or equal to 3-fold, greater than or equal to 4- fold, greater than or equal to 5-fold, greater than or equal to 10-fold, greater than or equal to 15- fold, greater than or equal to 20-fold, greater than or equal to 37.5-fold, greater than or equal to 50-fold, greater than or equal to 70-fold, greater than or equal to 80-fold, greater than or equal to 90-fold, greater than or equal to 100-fold, greater than or equal to 500-fold, greater than or equal to 1000-fold, greater than or equal to 10,000-fold, greater than or equal to 105-fold.

[0237] In some embodiments, a reagent may be immobilized on a surface of a probe via a covalent bond. Prior to such immobilization, the surface of the probe may be functionalized such that it comprises a plurality of functional groups suitable for forming such covalent bonds. For instance, the surface of the probe may be functionalized by reaction with a bifunctional reagent comprising a siloxane group that facilitates attachment to the probe and a functional group that facilitates the formation of a covalent bond with the reagent to be immobilized on the probe. As another example, the surface of the probe may be exposed to a plasma or other treatment that generates functional groups in situ that facilitate the formation of a covalent bond with the reagent to be immobilized on the probe. Non-limiting examples of suitable types of functionals group that facilitate the formation of a covalent bond with the reagent to be immobilized on the probe and / or fiber include hydroxyls, amines, and carboxyls.

[0238] Optical signals described herein and / or pursuant to methods described herein may comprise light reflected from an interface internal to a probe and / or light reflected from the end of a probe. Such light may comprise both types of light, light interference between these two types of light (e.g., interference between light supplied to the probe by a common light source system but traveling through optical pathways having different optical path lengths), the absence of either or both such type of light, and / or the absence of such interference. As two examples, light supplied by a probe may comprise interference between light that is reflected from two different interfaces associated with a probe and / or a species immobilized on a probe (e.g., an interface between an interior portion of a probe and a coating disposed on the internal portion of the probe, an interface between the species and the probe, an interface between the species and an environment external to the probe, an interface at the end of the probe) or the absence of such interference. Light comprising light reflected from an interface internal to the probe and light

[0239] 36

[0240] #14430292vl reflected from the end of the probe may be indicative of the amount and / or type of a species immobilized on the end of the probe.

[0241] Light that is reflected from an interface associated with a probe may be supplied to a probe from a light source system. Such a light source system may be optically coupled to a probe such that light is transmitted from the light source and across the probe (e.g., parallel to an optical axis of the probe). Upon reaching an end of the probe, the light may be transmitted out of the probe and / or may reflect from an interface between the probe and an environment external to the probe (and / or from the end of the probe). If there is a species immobilized on the probe, some light may reflect from the interface between the probe and the species and / or some light may be transmitted through the species. The species may also change the effective refractive index at the end of the probe and / or change the effective optical path length of the light transmitted through the probe. Light transmitted through the species will then encounter the environment with which the species is in contact. Some light encountering this environment may be transmitted into the environment with which the species is in contact (e.g., an environment external to the probe) and / or may reflect from the interface between the environment and the species.

[0242] It is also possible for probe described herein to have one or more internal interfaces at which reflection may occur. For instance, some probes may comprise one or more internal interfaces at which reflection can occur, such as an interface between a coating and an interior portion of the probe on which the coating is disposed.

[0243] Light reflected from one or more of the above-described locations (and / or any further locations) may travel back through the probe. If light is reflected from multiple locations (e.g., at an interface between the probe and a species immobilized on the probe, at an interface between a species immobilized on the probe and an environment external to the probe, at an interface between a coating disposed on an interior portion of the probe and a species immobilized on the probe, at an interface between an interior portion of the probe and a coating disposed thereon, from the end of the probe), such light may interfere which each other. Light interference may cause the intensity of the interfered light to be higher or lower depending on whether the interference is positive or negative, which may depend on the phase shift between the multiple sources of interfering light. The phase shift may depend on the differences in the path lengths traveled by the light prior to interfering, the refractive index of the material(s) through which the

[0244] 37

[0245] #14430292vl light passes prior to interfering, and / or on the wavelength of light. Thus, in some embodiments, light supplied by a probe and / or detected by an optical detector comprises light having a variety of wavelengths. Additionally, obtaining information about the intensity of interfered light across a variety of wavelengths may provide information about the presence or absence of a layer comprising a species immobilized on a probe, the thickness of such a layer, and / or the refractive index of such a layer. This information may be employed to determine the presence, absence, and / or amount of the species immobilized on the probe.

[0246] FIG. 17 depicts schematically one example of a process by which light comprising both an amount of the light that has been reflected from an interface internal to a probe and an amount of light that has been reflected from the end of a probe can be generated. As shown in FIG. 9, light that travels down a probe may reflect from an interface between a coating disposed on an interior portion of a probe and from an interface between a species immobilized on the probe and an environment external to the probe. The phase shift between these two sources of reflected light may depend on the amount of the species immobilized on the probe and on the wavelength of the reflected light, which may affect the intensity of the reflected light measured. Analysis of the intensity of the reflected light as a function of wavelength may therefore be employed to determine an amount of the species immobilized on the probe. As shown in FIG. 17, the intensity of the reflected light as a function of wavelength may form an interference pattern, and a change in the magnitude of the phase shift between light reflecting from two interfaces described herein may cause a wavelength shift of such an interference pattern.

[0247] Detection of light may be performed at one or more discrete points in time or over a period of time. Additionally, such detection may be performed in a manner that yields a single data point (e.g., an endpoint, the average intensity of light at a particular wavelength as measured over a period of time, the average intensity of light at a particular wavelength as computed by averaging a plurality of measurements of light intensity, the intensity of light at a particular wavelength as determined from a single measurement) and / or a plurality of data points. The plurality of data points may describe the variation of the light intensity over time (e.g., in a kinetic measurement), the variation of the light intensity as a function of position, and / or the variation of the light intensity as a function of wavelength. The plurality of data points may be obtained from different measurements that take place over different (overlapping or nonoverlapping) periods of time.

[0248] 38

[0249] #14430292vl In some embodiments, detecting light over time comprises detecting its variation over time. The variation may comprise an increase, a decrease, or a lack of variation. In some embodiments, the variation comprises the first derivative of the intensity of the light at one or more wavelengths. The variation in the intensity of the light (and / or one or more wavelengths thereof) over a period of time may be determined from multiple measurements made over the period of time that yield multiple values of the light intensities over the period of time.

[0250] In some embodiments, light detected by an optical detector described herein and / or pursuant to a method described herein comprises visible light. It is also possible for the light to comprise infrared light. Additionally, the light may be and / or comprise polarized light or unpolarized light.

[0251] A variety of suitable optical detectors may be employed in the instruments and methods described herein. In some embodiments, an instrument comprises a multi-channel optical detector and / or a method comprises detecting light with a multi-channel optical detector. The different channels may be used to detect different wavelengths of light. Advantageously, this may allow for the intensities of multiple wavelengths of light to be detected simultaneously, which may allow for measurements to be made more rapidly. It is also possible for an instrument to comprise multiple single-channel optical detectors and / or for a method to comprise detecting light with multiple single-channel detectors. In such embodiments, each singlechannel detector may be employed to detect a different wavelength.

[0252] Non-limiting examples of suitable types of optical detectors include photon-counting devices, spectrophotometers, spectrometers (e.g., Raman spectrometers, infrared spectrometers), polarization detectors, photodiodes, CCD / CMOS sensors, and imaging sensors. Such optical detectors may be configured to and / or capable of detecting a variation of an optical signal over one or more periods of time. For instance, such optical detectors may be able to make relatively rapid measurements of an optical signal and / or measure an optical signal over a relatively short period of time. It is also possible for some optical detectors to be configured to and / or capable of detecting a plurality of optical signals (e.g., a plurality of optical signals, each associated with a fluid and / or a sample of a fluid). In some embodiments, an optical detector is configured to and / or capable of detecting the intensity of light as a function of position (which, in turn, may allow for the detection of the intensity of light as a function of the angle from which it reflected from the probe) and / or detecting the intensity of light across a restricted angular range.

[0253] 39

[0254] #14430292vl In some embodiments, an optical detector comprises a transmissive collimator positioned to collimate light supplied thereto by a cable. A variety of suitable transmissive collimators may be employed in the optical detectors, instruments, and methods described herein. In some embodiments, a transmissive collimator is a lens and / or comprises one or more lenses (e.g., two or more lenses). Lenses having fixed focal lengths or adjustable focal lengths may be employed for this purpose. Non-limiting examples of suitable lenses include adjustable liquid lenses, adjustable focusing lenses, liquid crystal lenses, zoom lenses, and tunable acoustic gradient lenses. In some embodiments, a collimator comprises one or more cylindrically shaped lenses.

[0255] In some embodiments, an optical detector comprises a diffraction grating positioned to disperse light collimated by the transmissive collimator. This dispersed light may impinge on a detection element present in an optical detector, allowing for the detection of the dispersed light across multiple channels.

[0256] EXAMPLE 1

[0257] This Example describes an exemplary instrument.

[0258] FIG. 18 depicts one exemplary instrument. The exemplary instrument shown in FIG. 18 comprises a light source system, a current stabilizer (referred to therein as a “Constant Current Driver”), a temperature controller configured to control the temperature of one or more components of the light source system, a probe (referred to therein as a “BLI biosensor”), a cable (referred to therein as a “Fiber Optic Bundle”) placing the probe in optical communication with the light source system, an optical detector (referred to therein as a “Detector”), a temperature controller configured to control the temperature of one or more components of the optical detector, and a cable (referred to therein as a “Fiber Optic Bundle”) placing the probe in optical communication with the optical detector.

[0259] EXAMPLE 2

[0260] This Example describes a second exemplary instrument.

[0261] FIG. 19 depicts another exemplary instrument. The exemplary instrument shown in FIG. 19 comprises a light source system, a current stabilizer (referred to therein as a “Constant Current Driver”), a temperature controller configured to control the temperature of one or more components of the light source system, an optical multiplexer, a probe (referred to therein as a

[0262] 40

[0263] #14430292vl “BLI biosensor”), a cable (referred to therein as a “Fiber Optic Bundle”) placing the probe in optical communication with the optical multiplexer, an optical detector (referred to therein as a “Detector”), a cable (referred to therein as a “Fiber Optic Bundle”) placing the probe in optical communication with the optical detector, a temperature controller configured to control the temperature of one or more components of the optical detector, and a cable (referred to therein as a “Fiber Optic Bundle”) placing the optical multiplexer in optical communication with the optical detector, and a temperature controller.

[0264] EXAMPLE 3

[0265] This Example describes an exemplary light pipe.

[0266] FIG. 20 shows a mechanical drawing of the exemplary light pipe and FIG. 21 shows a photograph of the exemplary light pipe.

[0267] EXAMPLE 4

[0268] This Example describes exemplary holographic diffusers.

[0269] FIG. 22 shows a mechanical drawing of an exemplary holographic diffuser and FIG. 23 shows a photograph of four exemplary holographic diffusers. In FIG. 22, “FOB” refers to a cable that is a fiber-optic bundle.

[0270] EXAMPLE 5

[0271] This Example compares the performance of light source systems lacking a light diffuser and light source systems comprising various types of light diffusers.

[0272] Each light source system comprises an LED and a spectral broadener. For the light source systems that included a light diffuser, the light diffuser was positioned such that it was supplied with light emitted from the spectral broadener and light emitted by the LED and then transmitted through the spectral broadener. The light diffusers tested included a light pipe, and holographic diffusers having various diffusing angles. Each light source system supplied light from the light diffuser (or the spectral broadener if a light diffuser was absent) to a fiber-optic bundle.

[0273] Light was generated by the LED and spectral broadener in each light source system and then transmitted to and through the fiber-optic bundle. The intensity of the light transmitted

[0274] 41

[0275] #14430292vl through the fiber-optic bundle was measured as a function of position. This intensity was employed to compute a %MD value by the following equation:

[0276] „ . , , _ MAX-MIN

[0277] %MD = - ,

[0278] MAX+MIN where MAX was the maximum light intensity measured across the fiber-optic bundle and MIN was the minimum light intensity measured across the fiber-optic bundle. As can be seen from this equation, lower values of %MD are indicative of uniformity in the light intensity transmitted across the fiber-optic bundle.

[0279] FIGs. 24 and 25 show the %MD values for these various light source systems when driven at different current values (500 mA for FIG. 24 and 250 mA for FIG. 25). As can be seen from these Figures, the use of a light pipe (labeled therein as a “scrambler”) resulted in the lowest MD values and holographic diffusers having angles of 60° and 80° also displayed desirably low MD values. It is believed that such holographic diffusers displayed such low MD values because they had higher acceptance angles than the other holographic diffusers tested.

[0280] While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present invention is / are used. Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials,

[0281] 42

[0282] #14430292vl kits, and / or methods are not mutually inconsistent, is included within the scope of the present invention.

[0283] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0284] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0285] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0286] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0287] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily

[0288] 43

[0289] #14430292vl including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0290] It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

[0291] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

[0292] 44

[0293] #14430292vl

Claims

CLAIMSWhat is claimed is:

1. An instrument, comprising: a housing configured to receive a probe at a first location; an optical detector; and a light source system, wherein the light source system comprises: a light-emitting diode configured to emit light over a first wavelength range; a spectral broadener positioned optically between the first location and the lightemitting diode; and a temperature controller configured to control temperatures of the light-emitting diode and the spectral broadener, wherein the light source system is configured to supply light emitted by the spectral broadener to the first location.

2. A method, comprising: emitting light from a light-emitting diode over a first wavelength range; impinging the light emitted from the light-emitting diode on a spectral broadener; supplying light emitted by the spectral broadener to a probe, wherein the temperatures of the light-emitting diode and the spectral broadener are controlled by a temperature controller such that they vary by no more than 1.0 °C.

3. An instrument, comprising: a housing configured to receive a probe at a first location; an optical detector; a light source system, wherein the light source system comprises a light-emitting diode configured to emit light; and an optical multiplexer, wherein: the optical multiplexer is configured to divide light supplied thereto by the light source system into a first portion and a second portion,45#14430292vlthe optical multiplexer is configured to supply the first portion to the first location, and the optical multiplexer is configured to supply the second portion to the optical detector along a pathway that does not pass through the first location.

4. A method, comprising: emitting light from a light source system, wherein the light source system comprises a light-emitting diode configured to emit light; dividing the light emitted from the light source system into a first portion and a second portion; supplying the first portion to a probe; and supplying the second portion to an optical detector along a pathway that does not pass through the probe.

5. An instrument as in claim 1, wherein the instrument further comprises a cable.

6. An instrument as in claim 5, wherein the cable comprises a fiber-optic bundle.

7. An instrument as in claim 5, wherein the cable is configured to supply light emitted by the light source system to the first location.

8. An instrument as in claim 5, wherein the spectral broadener is configured to absorb light having a wavelength within the first wavelength range, and, upon such absorption, emit light over a second wavelength range, and wherein the light emitted over the second wavelength range is supplied to the probe by the cable.

9. An instrument as in claim 5, wherein the instrument further comprises a second cable.

10. An instrument as in claim 9, wherein the second cable comprises a fiber-optic bundle.46#14430292vl11. An instrument as in claim 9, wherein the second cable is configured to supply light transmitted through the probe to the optical detector.

12. An instrument as in claim 5, wherein light transmitted through the probe is supplied to the optical detector by the cable.

13. An instrument as in claim 5, wherein the instrument further comprises a focusing element positioned optically between the light source system and the cable.

14. An instrument as in claim 13, wherein the focusing element is a lens.

15. An instrument as in claim 13, wherein the focusing element is transmissive.

16. An instrument as in claim 5, wherein the instrument further comprises two or more focusing elements positioned between the light source system and the cable.

17. An instrument as in claim 16, wherein the focusing elements are lenses.

18. An instrument as in claim 16, wherein the focusing elements are transmissive.

19. An instrument as in claim 5, wherein the instrument further comprises a reflective element positioned optically between the light source system and the cable.

20. An instrument as in claim 19, wherein the reflective element is a mirror.

21. An instrument as in claim 5, wherein the instrument further comprises two or more reflective elements positioned between the light source system and the cable.

22. An instrument as in claim 21, wherein the reflective elements are mirrors.

23. An instrument as in claim 1, wherein the probe is an optical probe.47#14430292vl24. An instrument as in claim 23, wherein the probe comprises an optical fiber.

25. An instrument as in claim 1, wherein the spectral broadener is configured to absorb light having a wavelength within the first wavelength range, and, upon such absorption, emit light over a second wavelength range.

26. A method as in claim 2, further comprising absorbing the light emitted from the lightemitting diode with the spectral broadener, thereby stimulating the emission of light over a second wavelength range.

27. An instrument as in claim 25, wherein the second wavelength range comprises a wavelength that is outside the first wavelength range.

28. An instrument as in claim 25, wherein the second wavelength range extends from 190 nm to 1200 nm.

29. An instrument as in claim 25, wherein the spectral broadener is configured to emit light over the second wavelength range via luminescence.

30. An instrument as in claim 25, wherein the spectral broadener is configured to emit light over the second wavelength range via phosphorescence.

31. An instrument as in claim 1, wherein the temperature controller is configured to maintain the temperature of the light-emitting diode such that it varies by no more than 1 °C.

32. An instrument as in claim 1, wherein the temperature controller is configured to maintain the temperature of the spectral broadener such that it varies by no more than 1 °C.

33. An instrument as in claim 1, wherein the instrument further comprises a second temperature controller configured to control temperature of the optical detector.48#14430292vl34. An instrument as in claim 1, wherein the light-emitting diode is thermally insulated from the optical detector.

35. An instrument as in claim 1, wherein the light-emitting diode is thermally insulated from the spectral broadener.

36. An instrument as in claim 1, wherein the instrument further comprises a current stabilizer that is configured to maintain the current passing through the light-emitting diode.

37. An instrument as in claim 11, wherein the optical detector comprises a transmissive collimator positioned to collimate light supplied by the second cable.

38. An instrument as in claim 37, wherein the optical detector comprises a diffraction grating positioned to disperse light collimated by the transmissive collimator.

39. A method as in claim 4, further comprising detecting an optical signal generated from the first portion of the light by an optical detector.

40. A method as in claim 4, wherein the light emitted from the light source system comprises light emitted by the light-emitting diode.

41. An instrument as in claim 4, wherein the light source system comprises a spectral broadener, and wherein the light emitted from the light source system comprises light emitted by the spectral broadener.

42. A method as in claim 4, further comprising detecting the second portion of the light by the optical detector.49#14430292vl43. A method as in claim 42, further comprising determining whether the light emitted from the light source system varies with time based on the detection of the second portion of the light.

44. A method as in claim 42, further comprising detecting the first portion of the light, and wherein detecting the second portion of light comprises measuring an intensity of the second portion of the light, and wherein detecting the first portion of the light comprises measuring an intensity of the first portion of the light.

45. A method as in claim 44, further comprising normalizing the measured intensity of the second portion of the light by the measured intensity of the first portion of the light.

46. An instrument as in claim 1, wherein the instrument further comprises a plurality of lightemitting diodes.

47. An instrument as in claim 46, wherein the plurality of light-emitting diodes comprises light-emitting diodes that are configured to emit light over different wavelength ranges.

48. An instrument as in claim 1, wherein the instrument further comprises a light diffuser positioned optically between the light source system and the first location.

49. An instrument as in claim 48, wherein the light diffuser is configured to receive and mix the light from a plurality of light-emitting diodes positioned in the instrument.

50. An instrument as in claim 3, wherein the instrument further comprises a light diffuser positioned between the light source system and the optical multiplexer.

51. An instrument as in claim 48, wherein the light diffuser comprises a light pipe.

52. An instrument as in claim 51, wherein the light pipe is a hexagonal rod.

53. An instrument as in claim 48, wherein the light diffuser comprises a holographic diffuser.50#14430292vl

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