PATENT DOCUMENT

Publication Number: US-11579080-B2
Application Number: US-201816650804-A
Country: US
Kind Code: B2

Title: Resolve path optical sampling architectures

Abstract:
Described here are optical sampling architectures and methods for operation thereof. An optical sampling architecture can be capable of emitting a launch sheet light beam towards a launch region and receiving a detection sheet light beam from a detection region. The launch region can have one dimension that is elongated relative to another dimension. The detection region can also have one dimension elongated relative to another dimension such that the system can selectively accept light having one or more properties (e.g., angle of incidence, beam size, beam shape, etc.). In some examples, the elongated dimension of the detection region can be greater than the elongated dimension of the launch region. In some examples, the system can include an outcoupler array and associated components for creating a launch sheet light beam having light rays with different in-plane launch positions and/or in-plane launch angles.

Claims:
The invention claimed is: 
     
       1. A system comprising:
 at least one light emitter that emits light; 
 a system interface including: 
 a launch region from which the light emitted by the at least one light emitter is capable of exiting the system, wherein the launch region includes a first dimension and a second dimension, the second dimension of the launch region is elongated relative to the first dimension of the launch region, wherein the launch region is configured to form, from the light emitted by the at least one light emitter, a first launch sheet light beam having a cross-section with a second dimension that is elongated relative to a first dimension of a cross-section of the first launch sheet light beam as the first light beam exits the system, and 
 a detection region through which light is capable of entering the system, wherein the detection region includes a first dimension and a second dimension, the second dimension of the detection region elongated relative to the first dimension of the detection region, wherein the second dimension of the launch region is elongated along a same direction that the second dimension of the detection region is elongated, and wherein the detection region is configured to form, from the light entering the system, a second detection sheet light beam within the system, a cross-section of the second light beam having a second dimension that is elongated relative to a first dimension of a cross-section of the second detection sheet light beam; 
 a detector that detects at least a portion of the second detection sheet light beam and generates one or more signals indicative of the portion of the second detection sheet light beam; and 
 logic that determines one or more sample properties from the one or more signals. 
 
     
     
       2. The system of  claim 1 , wherein a size and a shape of the launch region is same as a size and a shape of the detection region. 
     
     
       3. The system of  claim 1 , wherein the second dimension of the detection region is longer than the second dimension of the launch region. 
     
     
       4. The system of  claim 1 , further comprising:
 optics selectively allowing the portion of the second detection sheet light beam to pass through to the detector, wherein the portion of the second light beam meets a change in angle criteria. 
 
     
     
       5. The system of  claim 4 , wherein the change in angle criteria includes a threshold range of angles based on a targeted optical path length. 
     
     
       6. The system of  claim 1 , wherein the detection region forms the second detection sheet light beam by selectively allowing light, from the light entering the system, that meets a change in angle criteria. 
     
     
       7. The system of  claim 1 , wherein the at least one light emitter includes one or more outcouplers and a reflector, the one or more outcouplers located a first separation distance from the reflector,
 wherein the one or more outcouplers are located a second separation distance from the launch region, 
 wherein the detector is located a third separation distance from the detection region, and 
 wherein a total of a targeted optical path length, the first separation distance, the second separation distance, and the third separation distance are equal to a focal length of the reflector. 
 
     
     
       8. The system of  claim 1 , further comprising:
 a multiplexer that: 
 receives the light emitted by the at least one light emitter, 
 forms, from the light emitted by the at least one light emitter, a third launch sheet light beam, and 
 outputs the third launch sheet light beam; 
 a phase control network that: 
 receives the third launch sheet light beam, and 
 controls a phase of at least a portion of the third launch sheet light beam; and 
 an outcoupler array including a plurality of outcouplers, the outcoupler array redirecting the third launch sheet light beam to the launch region. 
 
     
     
       9. The system of  claim 8 , wherein the third launch sheet light beam has one or more of: different in-plane launch angles and in-plane launch locations. 
     
     
       10. A method for using a system, the method comprising:
 emitting light using at least one light emitter; 
 forming a first launch sheet light beam from the light emitted by the at least one light emitter using a launch region, 
 wherein the launch region includes a first dimension and a second dimension, the second dimension of the launch region is elongated relative to the first dimension of the launch region; 
 allowing the first launch sheet light beam to exit the system through the launch region, wherein a cross-section of the first launch sheet light beam has a second dimension that is elongated relative to a cross-section of a first dimension of the first launch sheet light beam as the first launch sheet light beam exits the system; 
 allowing light to enter through the system through a detection region, wherein the detection region includes a first dimension and a second dimension, the second dimension of the detection region elongated relative to the first dimension of the detection region, 
 wherein the second dimension of the launch region is elongated along a same direction that the second dimension of the detection region is elongated; 
 forming a second detection sheet light beam from the light entering the system using the detection region, wherein a cross-section of the second detection sheet light beam has a second dimension that is elongated relative to a cross-section of a first dimension of the second detection sheet light beam; 
 detecting at least a portion of the second detection sheet light beam by a detector; 
 generating one or more signals indicative of the portion of the second detection sheet light beam detected by the detector; and 
 determining one or more sample properties from the one or more signals. 
 
     
     
       11. The method of  claim 10 , wherein forming the first launch sheet light beam includes selectively controlling one or more parameters of the light emitted by the at least one light emitter. 
     
     
       12. The method of  claim 10 , wherein forming the second detection sheet light beam includes selectively controlling one or more parameters of the light that has entered through the system using optics.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national phase application under 37 U.S.C. § 371 of PCT/US2018/053237, filed Sep. 27, 2018, which claims the benefit of U.S. Provisional Patent Application No. 62/565,789, filed on Sep. 29, 2017, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD 
     The disclosure is directed generally to an optical sampling architecture capable of measuring one or more sample properties. More specifically, the architecture can measure the sample and average the measured signals over multiple scale lengths while controlling the optical path lengths and optical sampling depths of the measured signals. 
     BACKGROUND 
     Absorption spectroscopy is an analytical technique that can be used to determine the sample properties. Conventional systems and methods for absorption spectroscopy can include emitting light toward a sample. As light interacts with (e.g., reflects and/or transmits through) the sample, a portion of the light energy can be absorbed at one or more wavelengths. This absorption can cause a change in the properties of light that interacts with the sample. The properties of light interacting with the sample can be compared to the properties of light interacting with a reference, and the sample properties can be determined based on this comparison. 
     The properties of light that exits the sample can be measured by one or more detector pixels. In some instances, the light transmitting through the sample may undergo diffuse scattering. In some instances, the sample may be a heterogeneous sample, where the sample properties may vary across different volumes in the sample. Diffuse scattering may involve light interacting with a relatively small sample volume, which may lead to increased sensitivity to inhomogeneity of the sample. As such, measurements of a relatively small sample volume may not be representative of the sample as a whole. An optical sampling architecture capable of measuring properties of the sample and averaging the signals over multiple scale lengths while controlling the optical path lengths and optical sampling depths of the measured signals may be desired. 
     In some examples, optical measurements can include noise. Noise can take multiple forms including incoherent and coherent. Incoherent noise can be due to diffuse scattering that may occur as light transmits through the sample, and its properties may be independent of the phases of light incident on the detector. In some instances, the sample may be inhomogeneous, where the sample properties may vary across different volumes in the sample. The inhomogeneity of the sample may contribute to incoherent noise through random distributions of diffuse scattering and the like. Incoherent noise may also vary depending on wavelength. Coherent noise can be due to, e.g., speckle, and its properties can depend on the phases of light incident on the detector along with the spectral density of the source power. In some architectures, both incoherent and coherent noise may be present and may be with varying percentages. An optical sampling architecture capable of reducing both incoherent and coherent noise may be desired. 
     SUMMARY 
     Described here are optical sampling architectures and methods for operation thereof. In some examples, an optical sampling architecture can be capable of emitting a launch sheet light beam from a launch region and receiving a detection sheet light beam from a detection region, where the emission and detection regions are located at the system interface. The launch region can have one dimension (e.g., y-dimension) that is elongated relative to another dimension (e.g., x-dimension) such that light output from one or more waveguides can collectively form the launch sheet light beam. The detection region can also have one dimension elongated relative to another dimension such that the system can selectively accept light having one or more properties (e.g., angle of incidence, beam size, and/or beam shape that meet one or more criteria). In some examples, the elongated dimension of the detection region can be greater than the elongated dimension of the launch region. Additionally or alternatively, the optics included in the system can be configured to selectively accept light. 
     As described here, a light emitter may be configured to form a launch sheet light beam. In some examples, the light emitter can include one or more waveguides, one or more reflectors, and an outcoupler. The one or more waveguides can output light (e.g., including light rays oriented in certain directions) along a first plane (e.g., in the plane of the substrate) towards the reflectors. In some examples, the waveguides can form portions of coherent light sources. The reflectors can direct light towards the outcoupler along a first plane, and the outcoupler can direct light to a second plane (e.g., perpendicular to the first plane, 60° relative to the first plane, 45° relative to the first plane, etc.). In some examples, the light emitter can be an incoherent source. The components of the light emitter along with the detector, launch region, and detection region of the system can be configured based on a targeted intersection points of light in the sample. 
     Examples of the disclosure can further include an outcoupler array and associated components for reducing coherent and/or incoherent noise. The outcoupler array and associated components can create a launch sheet light beam having different in-plane launch positions and/or in-plane launch angles. The associated components can include a multiplexer and a phase control network. The different in-plane launch positions and/or in-plane launch angles can be created using, for example, a staggered arrangement for the outcouplers included in the outcoupler array. In some examples, the system can include multiple optics for spatially separating the emitted light from the light emitter. Additionally or alternatively, the system can include multiple spatially distinct detection regions. In yet another example, the system can include divergence optics to create divergence in the emitted light from the light emitter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  illustrates a block diagram of an exemplary system according to examples of the disclosure. 
         FIG.  1 B  illustrates an exemplary process flow for measuring sample properties according to examples of the disclosure. 
         FIG.  2 A  illustrates a cross-sectional view of an exemplary system with multi-layered optics according to examples of the disclosure. 
         FIGS.  2 B- 2 C  illustrate exemplary light that have undergone a single large-angle scattering event according to examples of the disclosure. 
         FIG.  3 A  illustrates a planar view of an exemplary system interface and sample according to examples of the disclosure. 
         FIG.  3 B  illustrates an exemplary process flow for measuring sample properties using the system according to examples of the disclosure. 
         FIG.  3 C  illustrates an exemplary instance of accepting collected light within a threshold range of angles along the plane of the detection sheet light beam according to examples of the disclosure. 
         FIGS.  4 A- 4 D  illustrate top views of exemplary light emitter configurations for forming a launch sheet light beam according to examples of the disclosure. 
         FIG.  4 E  illustrates an exemplary process flow for forming a launch sheet light beam using a light emitter according to examples of the disclosure. 
         FIG.  5 A  illustrates a cross-sectional view of an exemplary system configured such that light intersect at a targeted location within the sample according to examples of the disclosure. 
         FIG.  5 B  illustrates a cross-sectional view of an exemplary system configured such that light intersect at the detector according to examples of the disclosure. 
         FIG.  5 C  illustrates a cross-sectional view of an exemplary system configured such that light intersect at the outcoupler according to examples of the disclosure. 
         FIGS.  6 A- 6 C  illustrate top views of exemplary incoherent light emitters including one or more coherent waveguides according to examples of the disclosure. 
         FIG.  7 A  illustrates an exemplary light emitter configuration where light collectively form a flat intensity distribution according to examples of the disclosure. 
         FIG.  7 B  illustrates an exemplary light emitter configuration having a spherical wavefront including multiple portions pointing in different directions according to examples of the disclosure. 
         FIG.  7 C  illustrates an exemplary light emitter capable of emitting light at multiple angles and along multiple locations according to examples of the disclosure. 
         FIG.  8    illustrates a planar view of an exemplary system interface and sample according to examples of the disclosure. 
         FIG.  9 A  illustrates a top view of an exemplary integrated photonics chip including an outcoupler array according to examples of the disclosure. 
         FIGS.  9 B- 9 C  illustrate top and cross-sectional views, respectively, of an exemplary outcoupler and waveguide according to examples of the disclosure. 
         FIG.  10    illustrates a top view of an exemplary integrated photonics chip including a two-sided outcoupler array according to examples of the disclosure. 
         FIG.  11    illustrates a cross-sectional view of an exemplary integrated photonics chip including a plurality of emissions regions according to examples of the disclosure. 
         FIG.  12    illustrates a cross-sectional view of an exemplary integrated photonics chip including a plurality of detection regions according to examples of the disclosure. 
         FIG.  13    illustrates a cross-sectional view of an exemplary integrated photonics device including one or more optics having properties for increasing entendue according to examples of the disclosure. 
         FIG.  14    illustrates a block diagram of an exemplary phase control network using an interleaved group delay according to examples of the disclosure. 
         FIG.  15    illustrates a block diagram of an exemplary direct phase control network according to examples of the disclosure. 
         FIG.  16    illustrates an exemplary integrated photonics chip including outputs from a phase control network used for multiple outcoupler arrays according to examples of the disclosure. 
         FIG.  17    illustrates an exemplary integrated photonics chip including outputs from a phase control network used for outcoupler arrays including multiple zones according to examples of the disclosure. 
         FIG.  18    illustrates an exemplary process flow for measuring sample properties using an integrated photonics device having an optical sampling architecture according to examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of examples, reference is made to the accompanying drawings in which it is shown by way of illustration specific examples that can be practiced. It is to be understood that other examples can be used and structural changes can be made without departing from the scope of the various examples. 
     Representative applications of methods and apparatus according to the present disclosure are described in this section. These examples are being provided solely to add context and aid in the understanding of the described examples. It will thus be apparent to one skilled in the art that the described examples may be practiced without some or all of the specific details. Other applications are possible, such that the following examples should not be taken as limiting. 
     Various techniques and process flow steps will be described in detail with reference to examples as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects and/or features described or referenced herein. It will be apparent, however, to one skilled in the art, that one or more aspects and/or features described or referenced herein may be practiced without some or all of these specific details. In other instances, well-known process steps and/or structures have not been described in detail in order to not obscure some of the aspects and/or features described or referenced herein. 
     Some samples may be heterogeneous with variations in sample properties along different areas within the sample. The varying structure of the sample can cause light emitted from the system to return (e.g., reflect, scatter, or otherwise be redirected) back toward the system, and the system can measure the return light. Additionally, the heterogeneous nature of a sample may lead to an inherit randomness in its optical absorption. This inherit randomness may lead to inaccurate measurements when the volume being measured in the sample is relatively small. In some instances, the measurements may have increased sensitivity to random scattering within the relatively small volume, where one or more factors (e.g., orientation, position, size of the particles, etc.) can lead to large deviations in the optical properties of the detected reflected light. These deviations can be reduced, the measurement accuracy can be enhanced, and the optical efficiency can be increased by increasing sample volume. The sample volume can include the volume to which emitted light traverses through the sample, undergoes a single scattering event, and can return to be received by the detector array. With an increase in the sample volume, the detector array can receive more light having useful signal information, where averaging of the received light can increase the signal-to-noise ratio. In some instances, configuring the system to measure and average the sample properties over a relatively larger sample volume (e.g., multiple scale lengths) can be more representative of the overall properties of the sample (instead of being representative of the local properties of the sample). 
     The heterogeneous nature of the sample can include the sample having multiple scattering sites, where light may deviate from its trajectory with scattering events (at the scattering sites). Different locations of the sample can have a pattern of noise, which may be wavelength dependent due to, e.g., different properties within the sample having different wavelength dependent absorption. The wavelength dependent pattern of noise can lead to decreased measurement accuracy. 
     To reduce or remove the noise included in the determination of the sample properties, the system can increase the percentage of measured signals having targeted optical path lengths and targeted optical sampling depths. Additionally or alternatively, the system may limit the light rays included in the analysis to those that have undergone a single scattering event. For example, the system can receive more light that has undergone a single scattering event relative to light that has undergone multiple scattering events. A single scattering event can occur when the emitted light and the detected light intersect in the sample. Thereby, at the single scattering event, the emitted light can turn around and reflect back towards the system to become the detected light. The likelihood of receiving light that has undergone a single scattering event can increase by controlling the parameters (e.g., beam shape, beam size, and angles) of light exiting the launch region and/or light entering the detection region. 
     In some instances, the emitted light may undergo multiple small-angle scattering events before reaching the single scattering event. In some instances, the output light may undergo multiple small-angle scattering events before reaching the detection region. Multiple small-angle scattering events may lead to a change in optical path length of light. In some examples, the change may be small enough such that the measurement accuracy may not be impaired and including such light may be lead to a better representation of the sample properties, as discussed below. A device capable of measuring over multiple scale lengths (e.g., multiple millimeters) within the sample while also controlling the optical path lengths and the optical sampling depths of the measured signals may be desired. 
     In some examples, optical measurements can include noise. Noise can take multiple forms including incoherent and coherent. Incoherent noise can be due to diffuse scattering that may occur as light transmits through the sample, and its properties may be independent of the phases of light incident on the detector. In some instances, the sample may be inhomogeneous, where the sample properties may vary across different volumes in the sample. The inhomogeneity of the sample may contribute to incoherent noise through random distributions of diffuse scattering and the like. Incoherent noise may also vary depending on wavelength. Coherent noise can be due to, e.g., speckle, and its properties can depend on the phases of light incident on the detector along with the spectral density of the source power. In some architectures, both incoherent and coherent noise may be present and may be with varying percentages. An optical sampling architecture capable of reducing both incoherent and coherent noise may be desired. 
     Described here are optical sampling architectures and methods for operation thereof. In some examples, an optical sampling architecture can be capable of emitting a launch sheet light beam from a launch region and receiving a detection sheet light beam from a detection region, where the emission and detection regions are located at the system interface. The launch region can have one dimension (e.g., y-dimension) that is elongated relative to another dimension (e.g., x-dimension) such that light output from one or more waveguides can collectively form the launch sheet light beam. The detection region can also have one dimension elongated relative to another dimension such that the system can selectively accept light having one or more properties (e.g., angle of incidence, beam size, and/or beam shape that meet one or more criteria). In some examples, the elongated dimension of the detection region can be greater than the elongated dimension of the launch region, where the planes of the elongated dimensions of both the detection region and the launch region can be parallel. Additionally or alternatively, the optics included in the system can be configured to selectively accept light. 
     Described here is a light emitter configured to form a launch sheet light beam. In some examples, the light emitter can include one or more waveguides, one or more reflectors, and an outcoupler. The one or more waveguides can output light along a first plane (e.g., in the plane of the substrate) towards the reflectors. In some examples, the waveguides can form portions of coherent light sources (also referred to as “coherent waveguides”). The reflectors can direct light towards the outcoupler along a first plane, and the outcoupler can direct light to a second plane (e.g., perpendicular to the first plane, 60°, 45°, etc.). In some examples, the light emitter can be an incoherent source. The components of the light emitter along with the detector, launch region, and detection region of the system can be configured based on the intersection points of light. 
     Examples of the disclosure can further include an outcoupler array and associated components configured to reduce coherent and/or incoherent noise. The outcoupler array and associated components can create a launch sheet light beam having different in-plane launch positions and/or in-plane launch angles. The associated components can include a multiplexer and a phase control network. The different in-plane launch positions and/or in-plane launch angles can be created using, for example, a staggered arrangement for the outcouplers included in the outcoupler array. In some examples, the system can include multiple optics for spatially separating the emitted light from the light emitter. Additionally or alternatively, the system can include multiple spatially distinct detection regions. In yet another example, the system can include divergence optics to create divergence in the emitted light from the light emitter. 
     Overview of the Integrated Photonics Device 
       FIG.  1 A  illustrates a block diagram of an exemplary system according to examples of the disclosure.  FIG.  1 B  illustrates an exemplary process flow for measuring sample properties according to examples of the disclosure. The system  100  can include an interface  180 , an optical unit  190 , a light emitter  107 , a detector  130 , and a controller  140 . The interface  180  can include an external surface (e.g., system interface  380  illustrated in  FIG.  3 A ) of a device which can accommodate light transmission there through. The interface  180  can include a launch region  182 , a reference  108  (optional), and a detection region  156 . In some examples, the launch region  182  can include an aperture layer including one or more features (e.g., openings) configured to shape one or more of the location(s), angle(s), and/or shape(s) of light exiting the system  100 . In some examples, the detection region  156  can include an aperture layer configured to limit the locations and/or angles of light entering the system  100 . By limiting the location and/or angles of light entering, the light incident on, or exiting from, a measured sample volume  120  can be selectively limited. The optical unit  190  can include an absorber or light blocker  192 , optics  191  (e.g., lenses), optics  194  (e.g., a negative micro-lens), and light collection optics  116  (e.g., a positive microlens). While operating the system  100 , the measured sample volume  120  can be located near, close to, or touching at least a portion (e.g., system interface) of the system  100 . The light emitter  107  can be coupled to the controller  140 . The controller  140  can send a signal (e.g., current or voltage waveform) to control the light emitter  107 , which can emit light (step  153  of process  151 ). The light emitter  107  can include a plurality of waveguides (discussed below). The light emitter  107  can emit light towards the launch region  182  (step  155  of process  151 ). 
     The launch region  182  can be configured to allow light to exit the system  100  to be incident on the measured sample volume  120 . Depending on the nature of the measured sample volume  120 , light can penetrate a certain depth into the measured sample volume  120  to reach one or more scattering sites and can return (e.g., reflect and/or scatter back) towards the system  100 . The return light can enter back into the system  100  at the detection region  156  (step  159  of process  151 ). The return light that enters back into the system  100  can be collected by light collection optics  116 , which can direct, collimate, focus, and/or magnify the return light (step  161  of process  151 ). The return light can be directed towards the detector  130 . The detector  130  can detect the return light and can send an electrical signal indicative of the amount of detected light to the controller  140  (step  163  of process  151 ). 
     Additionally or alternatively, the light emitter  107  can optionally emit light towards the reference  108  (step  165  of process  151 ). The reference  108  can redirect light towards optics  194  (step  167  of process  151 ). The reference  108  can include, but is not limited to, a mirror, a filter, and/or a sample with known optical properties. Optics  194  can direct, collimate, focus, and/or magnify light towards the detector  130  (step  169  of process  151 ). The detector  130  can measure light reflected from the reference  108  and can generate an electrical signal indicative of this reflected light (step  171  of process  151 ). 
     The controller  140  can be configured to receive one or more electrical signals from the detector  130 . In some instances, the detector  130  can receive at least two electrical signals, where one electrical signal can be indicative of light reflected/scattered from the measured sample volume  120 , and another electrical signal can be indicative of light reflected from the reference  108 . The different electrical signals can be a time-multiplexed signal, for example. The electrical signal at a given instance in time can be based on whether the light is sent to the measured sample volume or the reference. In other instances, two or more electrical signals can be received by different detector pixels simultaneously and may include different light information. The controller  140  (or another processor) can determine the properties of the sample from the electrical signals (step  173  of process  151 ). 
     In some examples, when the system is measuring the properties of the sample and the reference, light emitted from the light emitter  107  can reflect off a surface of the sample back into the system  100 . Light reflected off the system interface (e.g., interface where the system contacts the sample) can be referred to as the interface reflected light  184 . In some examples, interface reflected light  184  could be light emitted from the light emitter  107  that returns from the measured sample volume  120  or the reference  108  and can be due to light scattering within the system  100 . Since the interface reflected light  184  can be unwanted, the absorber or light blocker  192  can prevent the interface reflected light  184  from being collected by the optics  194  and the light collection optics  116 . In this manner, the system can prevent the interface reflected light  184  from being measured by the detector  130 . 
     Launch Beam 
     In some applications, the measurements of a relatively small sample volume may not lead to an analysis that is representative of the sample as a whole. For example, the measurement of a heterogeneous sample using light that undergoes diffuse scattering within the sample may lead to inaccurate measurements and analysis. To enhance the measurement accuracy, a launch beam that is elongated for measuring a larger sample volume may be desired. 
       FIG.  2 A  illustrates a cross-sectional view of an exemplary portion of a system with multi-layered optics according to examples of the disclosure. While operating the system, the measured sample volume  220  can be located close to the system interface. The measured sample volume  220  can include one or more locations, such as location  257 . In some examples, a location within the sample can include a scattering site associated with a scattering event. The system  200  can be configured to reconstruct the optical paths in the measured sample volume  220 . For example, the system  200  can be configured to reconstruct the angles and locations of light received at the detection region to another plane (e.g., a plane located closer to the detector array  230 ). Reconstruction of the optical paths can be performed using one or more layers of optics (e.g., optics  216 ). The system  200  can include two layers of optics, for example, as shown in the figure. The system  200  can include a support  214  to support the optics  216 . Located below (i.e., opposite the surface of the system interface) the optics  216  can be a detector array  230 . Located between the optics  216  can be air, vacuum, or any medium with a refractive index that contrasts the refractive indices of the optics  216 . Although the figure illustrates a system including two-layers of optics, examples of the disclosure can include, but are not limited to, any number (e.g., one, three, four, etc.) of layers of optics. As another example, the system may associate certain detector pixels with different optical path lengths to determine (e.g., estimate) the optical properties (e.g., absorbance) of the measured sample volume  220 . 
     The system  200  can include a light emitter  207 . The light emitter  207  can be configured to emit light  250 . The light emitter  207  can include any light source (including one or more waveguides  201 ) capable of generating light. In some instances, the light source can be a single light source. In other instances, the light emitter  207  can include a plurality of discrete light sources. A light source can include, but is not limited to, a lamp, laser, light emitting diode (LED), organic light emitting diode (OLED), electroluminescent (EL) source, quantum dot (QD) light emitter, super-luminescent diode, super-continuum source, fiber-based source, or a combination of one or more of these sources. In some examples, the light emitter  207  can be capable of emitting a single wavelength of light. In some examples, the light emitter  207  can be capable of emitting a plurality of wavelengths of light. In some examples, the light emitter  207  can be any tunable source capable of generating a short-wave infrared (SWIR) signature. In some examples, each of the waveguides  201  included in the light emitter  207  can output a different wavelength range of light (e.g., different colors in the spectrum). In some examples, a waveguide  201  can include a III-V material, such as Indium Phosphide (InP), Gallium Antimonide (GaSb), Gallium Arsenide Antimonide (GaAsSb), Aluminum Arsenide (AlAs), Aluminum Gallium Arsenide (AlGaAs), Aluminum Indium Arsenide (AlInAs), Indium Gallium Phosphide (InGaP), Indium Gallium Arsenide (InGaAs), Indium Arsenide Antimonide (InAsSb), Indium Phosphide Antimonide (InPSb), Indium Arsenide Phosphide Antimonide (InAsPSb), and Gallium Iridium Arsenide Antimonide Phosphide (GaInAsSbP). 
     Light from the waveguides  201  may also be controlled using an integrated tuning element  204 . The integrated tuning element  204  may be part of the light emitter  207  as shown, or may be a component separate from the light emitter  207  (not shown). Light from the waveguides  201  can be combined using optical traces (not shown) and a multiplexer (not shown). In some examples, the integrated tuning element  204 , the optical traces, and the multiplexer can be disposed on a substrate  242  or included in a single optical platform, such as an integrated silicon photonics chip. In some examples, the system  200  may include one or more of optical attenuators, phase modulators, splitters, and the like (discussed below). 
     The system  200  can also include a thermal management unit  202  for controlling (e.g., heating or cooling) the temperature of the light emitter  207 . The light emitter  207  may include one or more outcouplers  209 . The outcoupler  209  can optionally be configured to focus, collect, collimate, and/or condition (e.g., shape) light from the waveguides  201  towards at least a portion of the optics  216 . In some examples, the outcoupler  209  can be configured as a single mode waveguide that directs the light beam towards optics  216  in such a manner that the angles of exiting light are restricted. In some examples, light  250  from the outcoupler  209  can be a launch sheet light beam (discussed below). The optics  216  can receive light  250  and can collimate and/or tilt the light beam towards the launch region  282  and towards one or more locations (e.g., location  257 ) in the measured sample volume  220 . In some examples, the optics  216  can include a lens having a bottom surface (i.e., surface facing the outcoupler  209 ) that is flat or almost flat (e.g., within 10%) and a top surface (i.e., surface facing away from the outcoupler  209 ) that is convex. Light can be emitted from the waveguides  201 , collimated by the outcoupler  209 , transmitted through optics  216 , and exit the system  200  through launch region  282  can be referred to as light  252 . 
     In some instances, light that interacts with the measured sample volume  220  can undergo one or more scattering events before exiting the measured sample volume  220 . The system can increase the percentage of measured signals having targeted optical path lengths and targeted optical sampling depths and/or limit the light rays included in the analysis to those that have undergone a single scattering event.  FIGS.  2 B- 2 C  illustrate exemplary light that have undergone a single large-angle scattering event according to examples of the disclosure. For example, as illustrated in  FIG.  2 B , light ray  252 A can be emitted light that undergoes a single large-angle scattering event at scattering site  258 A, resulting in the light ray  254 A. Neither light ray  252 A nor light ray  254 A may undergo other scattering events, so the system can include the signals associated with a targeted optical path length and targeted optical sampling depth (e.g., via selecting the light ray(s) based on the angles of the emitted light ray  252 A and the detected light ray  254 A) included in the sample analysis. 
     In some instances, emitted light, detected light, or both can experience multiple scattering events. For example, as illustrated in  FIG.  2 C , the emitted light ray  252 B can undergo multiple small-angle scattering events at the scattering sites  258 C before reaching the scattering site  258 B. The small-angle scattering events can create a small (e.g., less than 30°) change in the angle of light relative to its trajectory, where the direction of light can remain the same. At the scattering site  258 B, the light ray  252 B can undergo a single large-angle scattering event, resulting in the detected light ray  254 B. In some examples, the scattering site  258 B may be at a different location than the scattering site  258 A (e.g., due to small changes in angles associated with the small-angle scattering events). The single large-angle scattering event can change the direction of light. Additionally or alternatively, the detected light ray  254 B may undergo multiple small-angle scattering events at the scattering sites  258 C before reaching the detection region  256 . In some examples, the small-angle scattering events can lead to the detected light ray  254 B entering the detection region  256  at a different location than the detected light ray  254 A. 
     With light undergoing multiple small-angle scattering events, the optical path length can change (e.g., increase) slightly, but may have a minimal effect on the measurement accuracy. To ensure the effect is minimal, the system can be configured to include more return light that has the targeted optical path lengths and the targeted optical sampling depths in the sample analysis (e.g., to determine the sample properties). The emitted light exiting the launch region  282  (and emitted from the system to the sample) and the light entering the detection region  256  (which exited the sample) can be selected based on whether the optical path length of the return light is within a threshold range from the targeted optical path length. In some instances, light that have undergone multiple small-angle scattering events can be selectively allowed to pass through the detection region  256  to the detector (e.g., detector  130 ), and the system can prevent (or remove from the analysis) light that have undergone multiple large-angle scattering events from reaching the detector. 
     In some instances, the ratio of the number of small-angle to large-angle scattering events can be 10:1 or 20:1. In some examples, one or more criteria can be associated with one or more beam parameters including, but are not limited to, a range of areas (e.g., the area occupied by the detection region of the system) and a range of angles of light entering the system (and exiting the sample). 
       FIG.  3 A  illustrates a planar view of an exemplary system interface and measured sample volume according to examples of the disclosure.  FIG.  3 B  illustrates an exemplary process flow for measuring sample properties using the system according to examples of the disclosure. The system interface  380  can include a launch region  382  and a detection region  356 , where the regions can be configured such that one dimension is elongated relative to the other dimensions. For example, the launch region  382  can be rectangular (i.e., a stripe geometry) with the y-dimension being elongated relative to the x-dimension. For example, the launch region  382  can have a length that is multiple factors (e.g., 10, 15, 20, 25, etc.) greater than its width. 
     The light emitter (e.g., light emitter  207  of  FIG.  2 A ) can be configured to generate multiple light rays  352  (step  358  of process  350 ). In some examples, the light rays  352  can collectively form a launch sheet light beam  353  (instead of a linear light beam). The launch sheet light beam  353  can be formed by a single light emitter or multiple light emitters. In some examples, the system can be configured (e.g., by including spherical or cylindrical lenses) such that some or all of light rays  352  can be oriented parallel or within a spreading range (e.g., within ±5°) from each other. The distribution of the light rays  352  can be along the elongated y-direction. In this manner, the light rays  352  can extend in the y-direction creating a scatter voxel within the measured sample volume  320  at the location  357 . The scatter voxel can be a volume within the measured sample volume  320  where the launch sheet light beam  353  intersects with the detection sheet light beam  355 . 
     The launch sheet light beam  353  can exit the system through the launch region  382  (step  360  of process  350 ). Light may undergo one or more small-angle scattering events before reaching the location  357 . Light (e.g., light rays  352 ) included in the launch sheet light beam  353  can undergo a single large-angle scattering event at the location  357  within the measured sample volume  320  (step  362  of process  350 ). In some examples, the scatter voxel at location  357  can be longer (e.g., in the y-dimension) than the launch region  382  due to the spreading of the light rays  352 . For example, the scatter voxel can be 0.5 mm longer in the y-dimension than the launch region  382 . The spreading may be due to one or more scattering events causing a change in angles of some of the light rays. Some of the light rays  352  included in the launch sheet light beam  353  can reflect at the location  357  to form the light rays  354 . The light rays  354  can collectively form at least a portion the detection sheet light beam  355  (instead of a linear light beam) (step  364  of process  350 ). In some instances, the light rays  354  included in the detection sheet light beam  355  can undergo multiple small-angle scattering events before reaching the detection region  356 . 
     The detection region  356  and/or one or more components of the system (e.g., optical unit  190  illustrated in  FIG.  1 A ) can constrain or select light in the plane of the detection sheet light beam  355  (step  366  of process  350 ). The detection sheet light beam  355  can enter the system through the detection region  356 . The detection region  356  can also be configured such that one dimension is elongated relative to the other dimensions. The elongated dimension can be the y-dimension, which can be the same elongated dimension as the launch region  382 . In some examples, the size and shape of the launch region  382  and the detection region  356  can be the same. In some examples, the detection region  356  can be longer (e.g., in the y-dimension) than the launch region  382  to collect more light that may undergo multiple small-angle scattering events (discussed earlier). For example, the detection region  356  can be 1 mm longer in the y-dimension than the launch region  382 . A detector can receive the detection sheet light beam  355  and can generate one or more signals indicative of the detection sheet light beam  355  (step  368  of process  350 ). A processor can use the signals to determine the sample properties (step  370  of process  350 ). 
     Additionally or alternatively, the optics (e.g., optics  194 ) can be configured to constrain or select the scattering angles in the plane of the detection sheet light beam  355 . In some instances, the angle(s) of the light rays  352  included in launch sheet light beam  353  may change at location  357 . The change in angle(s) can be along the plane (e.g., with respect to the elongated portion of the detection region  356 ) of the detection sheet light beam  355 . The optics can be configured to selectively accept (e.g., allow light to pass through to the detector) changes in angle(s) that are within a threshold range of angles. That is, light included in the detection sheet light beam  355  can meet a change in angle criteria. Selectively acceptance can include rejecting (e.g., preventing light from reaching the detector) changes in angle(s) outside of a threshold range of angles. In some examples, the detection region  356  and/or optics can include one or more apertures that can, additionally or alternatively, accept changes in angle(s) within the threshold range of angles. 
       FIG.  3 C  illustrates an exemplary instance of accepting collected light within a threshold range of angles along the plane of the detection sheet light beam according to examples of the disclosure. The light ray  352 A can have a first angle of incidence (e.g., parallel to an edge of the launch sheet light beam  353 ) at the location  357 A, where a scattering event can occur. The scattering event can result in the light ray  354 A, which can have a second angle as the angle of return. In some instances, the threshold range of angles can be centered around the second angle, and the system can allow the light ray  354 A to pass through the detection region  356 . Alternatively, a single large-angle scattering event, multiple small-angle scattering events, or both within the sample can lead to the light ray  354 B, which may have a third angle as the angle of reflection. If the third angle is within the threshold range of angles, the optics can allow the light ray  354 B to pass through to the detection region  356 . 
     Some light, such as the light ray  354 C, may have an angle outside of the threshold range of angles. In some instances, the detection region  356  can reject the light ray  354 C. In some examples, the light ray  354 C may pass through the detection region  356 , and the optics can prevent the light ray  354 C from passing through to the detector. The threshold range of angles can ensure that the optical path lengths of the light rays used in the analysis or analyses of the sample properties are controlled. 
     The threshold range of angles can be based on one or more factors such as the targeted optical path length. For example, although the light ray  354 B could have a longer optical path length than the light ray  354 A, the difference between the optical path lengths of the light ray  354 A and the light ray  354 B may not have a significant effect on the measurement accuracy. The light ray  354 C may have an unwanted impact (e.g., the optical path length may be too long, light may have has undergone multiple large-angle scattering events, etc.), so the system can prevent the detector from measuring the light right  354 C (and/or prevent the controller from including such information in the analysis). A configuration of optics (for rejecting light with angles outside of the threshold range of angles) can include, but is not limited to, multiple cylinder lenses and a spherical lens with an aperture located between the spherical lens and the detector. 
     The system can be capable of emitting light that collectively form the launch sheet light beam  353  and capable of selectively measuring light that collectively form the detection sheet light beam  355 . As discussed above, light in the plane of the launch sheet light beam  353  and the detection sheet light beam  355  can have optical path length(s) within a threshold range from the targeted optical path length. To account for variations in the sample properties for, e.g., a heterogeneous sample, the system can average the signals indicative of the detected light from the detection sheet light beam  355 , where the stripe geometry can allow for increased spatial averaging. Increasing emitted light, detected light, or both can enhance the measurement accuracy (e.g., such that noise can be averaged out). In some examples, the illumination intensity of the emitted light can be uniform. In some examples, the detected light can be processed with some or all of light having the same weight. 
       FIG.  4 A  illustrates a top view of an exemplary light emitter configuration for forming a launch sheet light beam according to examples of the disclosure.  FIG.  4 E  illustrates an exemplary process flow for forming a launch sheet light beam using a light emitter according to examples of the disclosure. The light emitter  407  can include one or more waveguides  401 , which can be single mode waveguides located in a plane (e.g., plane  513  illustrated in  FIG.  5 A ) of the substrate  442 . The waveguides  401  can be terminated at respective termination points  403  for each waveguide, which can be a transition point to a free propagation region. The transition to the free propagation region can cause light output by the waveguides  401  to diffract with a divergence angle (e.g., ±1°, ±2°, ±3°, ±5°, etc.). For example, light from a waveguide  401  can diffract at the termination point  403  to form a divergent light beam including light  452 A and light  452 B (step  454  of process  450 ). A layer (not shown) (e.g., a layer including an oxide material) can be disposed on the substrate  442  (e.g., a silicon substrate) to guide light from the waveguides  401  in the plane of the substrate  442 , so the diffraction of the emitted light can be limited to in-plane divergence. 
     The light can be incident on a reflector  411  (step  456  of process  450 ). The reflector  411  can be a facet (e.g., a parabolic facet) configured to direct (e.g., turn at least some of light by 90°) and collimate the diverged beam towards the outcoupler  409  (step  458  of process  450 ). The reflector  411  can be an etched and/or metalized material such as a mirror. In some instances, the reflector  411  can have a curved shape, such as a parabolic shape, and can reflect light based on total internal reflection (TIR). The outcoupler  409  can direct the light out of the plane (e.g., perpendicular to the plane of the substrate  442 , 60° relative to the plane of the substrate  442 , 45° relative to the plane of the substrate  442 , etc.) toward optics (e.g., optics  216  illustrated in  FIG.  2 A ), a launch region (e.g., launch region  182  illustrated in  FIG.  1   ), and a sample (e.g., measured sample volume  220  illustrated in  FIG.  2 A ) (step  460  of process  450 ). In some examples, the outcoupler  409  can include one or more angled facets. In this manner, a collimated beam can be generated in a first plane (e.g., plane  513  illustrated in  FIG.  5 A ) and output in a second plane (e.g., perpendicular to the first plane, 60° relative to the first plane, 45° relative to the first plane, etc.). In some instances, the outcoupler  409  can direct the light out of the plane at a pre-determined angle, which may be selected based on the system design (as discussed below). 
     The waveguides  401  (and termination points) can be positioned at different locations on the plane of the substrate  442  (as shown), and light exiting the same termination point can be incident on reflector  411  at different locations. That is, the waveguides  401  can be located on the same plane as the reflector  411  and can output light along the same plane, but the light can be incident at different locations along the reflector  411 . For example, one waveguide (e.g., left most waveguide  401  shown in the figure) can be located closer to the outcoupler  409  and can output light which may be incident on the reflector  411  at a location closer to the outcoupler  409 . 
     There can be any number (e.g., 1, 3, 16, etc.) of waveguides  401  and termination points. In some examples, light incident at different locations of the reflector  411  can reflect to different locations along the outcoupler  409 . For example, light  452 A and light  452 B can exit the same termination point  403 . Light  452 A can be incident on the reflector  411  at location  412 A and can be directed to location  415 A of the outcoupler  409 . Light  452 B can be incident on the reflector  411  at location  412 B and can be directed to location  415 B of the outcoupler  409 . In some instances, different locations at the outcoupler  409  can be associated with different locations along the sample (e.g., the outcoupler  409  can direct light to a different plane without changing the angles of light). In this manner, light from the same waveguide can pass through the launch region (e.g., launch region  382  illustrated in  FIG.  3 C ) and enter the sample at different locations. Light emitted in the plane of the substrate  442  can cross each other, as illustrated in the figures, and can exit the launch region at multiple angles. In some examples, light from the same waveguide  401  can pass through the launch region at the same location, but can have different angles. In this manner, the system may be configured to measure different locations within the measured sample volume and/or the same location, but with light having different angles. 
     In some examples, the reflector can be configured to turn light by less than 90°, as illustrated in  FIG.  4 B , due to, e.g., its curvature and/or length. Turning light by less than 90° may lead to a wider spread of light along the outcoupler  409  (and along the sample). The curvature and/or length of the reflector can be configured based on the size of the outcoupler  409 , the dimensions of the elongated portion of the launch region, etc. The waveguides  401  can be located, for example, proximate to the reflector  411  and can include facets oriented perpendicular to the outcoupler  409 . 
     In some examples, the system can include multiple reflectors (e.g., reflector  411  and reflector  417 ), as illustrated in  FIG.  4 C . Multiple reflectors can be used to turn light by more than 90° and/or can include multiple turns. In some examples, the facets of the waveguides  401  can be oriented parallel to the outcoupler  409 . The waveguides  401  can direct light towards the reflector  417 , which can turn light to be incident on the reflector  411 . In some instances, the reflector  417  may be a flat mirror, while the reflector  411  may be a parabolic mirror. A configuration including multiple reflectors and multiple turns can be suitable when space is limited. 
       FIG.  4 D  illustrates an exemplary configuration where the waveguides may route light from multiple sides (e.g., top and bottom) of the substrate  442 . The reflector  411  can include a plurality of sections, such as section  411 A and section  411 B. The sections may be arranged differently. For example, the section  411 A may be arranged with a different (e.g., 90°) principal of axis than the section  411 B. The section  411 A may direct light from one side (e.g., the top) of the substrate  442  to the outcoupler  409 , and the section  411 B may direct light from another side (e.g., the bottom) of the substrate  442 . 
     The system can be configured based on the intersection points of light having the same optical path lengths.  FIG.  5 A  illustrates a cross-sectional view of an exemplary system configured such that light intersect at a targeted location within the sample according to examples of the disclosure. The outcoupler  509 , the plane  513 , optics  516 , the measured sample volume  520 , the system interface  580 , and the launch region  582  can be similar to correspondingly labeled elements from the other figures. The waveguides (not shown) can be configured to output light towards the outcoupler  509  at multiple locations (e.g., location  515 A and location  515 B). Light can pass through optics  516  and can exit the system interface  580  at the launch region  582 . Light can intersect at multiple locations (e.g., location  557 A, location  557 B, and location  557 C) within the measured sample volume  520 . The locations can have a depth  521 . As illustrated in the figure, light, which can have different angles of incidence, can cross at a location and can scatter from their respective locations towards the detector (e.g., detector  130  illustrated in  FIG.  1 A ). 
     In some examples, the average widths of the light beams in the measured sample volume  520  can be less than the average widths of the light beams at the optics  516 . The average widths of the light beams at the optics  516  can be less than the average widths of the light beams at the outcoupler  509  and the reflector (not shown). In some examples, the average widths of the light beams at the detector (not shown) can be less than the average widths of the light beams at the optics  516 . In this manner, the detector size (not shown) can be reduced at the tradeoff of a larger outcoupler  509 . This configuration (where light intersect within the sample) can be suitable for systems with a moderately sized detector, outcoupler, and launch region. In some examples, the width of the outcoupler  509  can be greater than the width of the optics  516 . 
     Examples of the disclosure include configuring the system such that light intersect at intersection points (e.g., at the detector) after undergo scattering events, as illustrated in FIG.  5 B. That is, light may intersect at multiple locations (e.g., location  558 A, location  558 B, and location  558 C) at the detector. Light may cross at the outcoupler  590 , optics  516 , the launch region  582 , and the measured sample volume  520 . In some examples, the average widths of the light beams can decrease as the light beams are further away from the reflector (not shown). For example, the average widths of the light beams, optics  516 , and/or the outcoupler  509  can be greater than the average widths at the detector within the measured sample volume. In this manner, the detector size (not shown) can be reduced at the tradeoff of a larger outcoupler  509 . This configuration (where light intersect at the detector) can be suitable for systems with a small detector and/or large outcoupler. 
       FIG.  5 C  illustrates another exemplary configuration where light intersect at the optics according to examples of the disclosure. Light may intersect at multiple locations, including location  515 A, location  515 B, and location  515 C, along the optics  516 . After intersecting, light may diverge creating average widths (of the light beams) that increase after the outcoupler  509 . The average widths may be smallest at the outcoupler  509  and largest at the detector (not shown). In this manner, the detector can be larger at the tradeoff of a smaller outcoupler  509 , the launch region  582 , optics  516 , and/or the integrated photonics chip. This configuration (where light intersect at the optics) can be suitable for systems with a larger detector and/or optics. Although  FIGS.  5 A- 5 C  illustrate configurations where light intersect within the sample, at the detector, and at the optics, examples of the disclosure can include light intersecting at any other locations such as the outcoupler. 
     In the above-disclosed configurations, examples of the disclosure can include light splitting at the intersection points, where light can split evenly across waveguides. Additionally or alternatively, examples of the disclosure can include the separation distance between the waveguides (e.g., waveguide  401 A) and the reflector(s) being equal to the focal length of the reflector. The intersection points can be located a distance equal to the focal length relative to the reflector. The space between the intersection points and the reflector can include the reflector, the outcoupler, the sample, and/or the detector. For example, in  FIG.  5 A , the intersection points, located at depth  521 , can be located a distance away from the reflector equal to the focal length of the reflector. That is, the sum of the separation distance(s) from the reflector to the outcoupler, from the outcoupler to the optics, and from the optics to the target depth in the sample can be equal to the focal length of the reflector. Each distance can be normalized to the refractive index of the respective material(s). 
     As another example, in  FIG.  5 B  where the intersection points are located at the detector, the separation distance (e.g., accounting for the change in plane at the outcoupler) between the detector and the reflector can be equal to the focal length of the reflector. In this manner, the distance from the reflector to the outcoupler in one plane along with the distance from the outcoupler to the system interface (e.g., the launch region) in another plane, the targeted optical sampling depth, and the distance from the system interface (e.g., the detection region) to the detector can be equal to the focal length of the reflector. In  FIG.  5 C , the separation distances from the reflector to the outcoupler  509  and from the outcoupler  509  to the optics  516  can be equal to the focal length of the reflector. The sum of the separation distance(s) can be normalized to the refractive index of the respective material(s). 
     In some instances, the light emitter can include a plurality of coherent sources that collectively approximate an incoherent source.  FIGS.  6 A- 6 C  illustrate exemplary configurations of an incoherent light emitter including one or more coherent waveguides according to examples of the disclosure. As illustrated in  FIG.  6 A , light emitter  607 A can include an outcoupler  609 , a waveguide  601 , and a reflector  611 , which can be similar to correspondingly labeled elements from the other figures. The waveguide  601  can further include a plurality of optical attenuators  604  and a splitter  606 . 
     A splitter  606  can be optionally included in the light emitter and can be configured to split the light emitted by the light sources  605 . In some examples, the light emitted by the light source can be along a first plane. In some examples, the light emitter can include a plurality of discrete light sources (not shown), and the splitter  606  may be omitted. The outputs of the splitter  606  can be fed into the optical attenuators  604 . The light emitter  607 A can include one or more waveguide termination points (not labeled in the figure), which can be transition points to a free propagation region. The transition to the free propagation region can cause light output by the waveguide  601 , e.g., at the optical attenuators  604 , to diffract with a divergence angle (e.g., ±1°, ±2°, ±3°, ±5°, etc.). 
     Light exiting the optical attenuators  604  can be directed by the reflector  611  towards the outcoupler  609 . Instead of sequentially outputting light from the waveguides (e.g., by using switches and/or modulators), the light source  607  can output light while the optical attenuators  604  can block or allow light to reach the reflector  611 . Alternatively, the light emitter  607 A can include one or more phase modulators (not shown) to induce a phase shift (e.g., 180°) in at least one of light. 
     The light emitter  607 A can emit multiple light beams, such as light  652 A, light  652 B, and light  652 C. The system can average the signals to reduce or eliminate the noise pattern. In this manner, the light emitter  607 A can be a source that is coherent in one dimension (e.g., in the plane of the substrate  642 ) and incoherent in another dimension (e.g., in the plane of the light  652 A, light  652 B, and light  652 C). Although the figure illustrates light  652 A, light  652 B, and light  652 C as emitted from the outcoupler  609  in the plane of the substrate  642 , examples of the disclosure can include the light beams emitted in other planes (e.g., the plane perpendicular to the plane of the substrate  642 ). Other exemplary configurations for reducing noise are discussed below. 
     In some instances, the light emitter may include a multiplexer for spatially combining multiple wavelengths of light. The multiplexer may cause optical losses and/or consume space on the integrated photonics chip.  FIG.  6 B  illustrates an exemplary light emitter with spatially combined wavelengths of light that excludes a multiplexer according to examples of the disclosure. The light emitter  607 B can include multiple waveguides  601 . The waveguides  601  can include facets placed in close proximity to one another while arranged such that the facets are angled differently with respect to the outcoupler  609 . For example, the facet of the waveguide  601 A can be oriented parallel to the outcoupler  609 , while the facet of the waveguide  601 B can be tilted (e.g., 5°) with respect to the same side of the outcoupler  609 . Light from at least two of the waveguides  601  can output in different directions, where the differences can create a shift in the light beams, as illustrated with light  652 A, light  652 B, and light  652 C. In some examples, the waveguides  601  can be oriented such that the light beams exit the launch region (e.g., launch region  582  illustrated in  FIG.  5 A ) at different angles. In some examples, the waveguides  601  can be oriented such that the light beams exit at different locations of the launch region. Examples of the disclosure can include one or more reflectors (not shown) to turn light (discussed above). 
     In some examples, the light emitter can include sets of waveguides, as illustrated in  FIG.  6 C . The light emitter  607 C can include the first plurality of waveguides  601 A, the second plurality of waveguides  601 B, and the third plurality of waveguides  601 C, where the pluralities of waveguides can be oriented such that the facets of the waveguides within a set are angled differently with respect to the other sets of waveguides. For examples, the first plurality of waveguides  601 A can be oriented at a first angle with respect to the principal axis of the reflector, while the second plurality of waveguides  601 B can be oriented at a second angle, and the third plurality of waveguides  601 C can be oriented at a third angle. In some examples, at least two (e.g., all) waveguides included in the same set can output a different wavelength of light. The different wavelengths of light in the same set can create a plurality of light beams (e.g., light  641 , light  643 , and light  653 ) each having different wavelengths. In some examples, waveguides within a set can be different, while each set can include the same type of waveguides as the other sets. 
     In some examples, the plurality of waveguides can be oriented such that the light beams exit the launch region (e.g., launch region  582  illustrated in  FIG.  5 A ) at different angles. For example, light  643  can include a plurality of wavelengths, where at least two of the wavelengths can be output from different waveguides. Light  652  can also include the plurality of wavelengths, where at least two of the wavelengths can be output from different waveguides. Light  652  can exit the launch region at a first angle, while light  643  can exit the launch region at a second angle. In some examples, the pluralities of waveguides  601  can be oriented such that the light beams exit at different locations of the launch region  682 . 
     As discussed earlier, the light emitter can emit light having different angles. In some examples, the different angles can be multiplexed angles. For example, the light emitter can be configured to emit multiple plane waves. Emitting multiple plane waves can be achieved by, e.g., using a collimating parabolic reflector. 
     In some examples, the light emitter can be configured to emit multiple spherical waves, as shown in  FIGS.  7 A- 7 C .  FIG.  7 A  illustrates an exemplary light emitter configuration where light can collectively form a flat intensity distribution according to examples of the disclosure. The light emitter can include one or more sets of waveguides (e.g., a first plurality of waveguides  701 A, a second plurality of waveguides  701 B, a third plurality of waveguides  701 C, and a fourth plurality of waveguides  701 D). Each set of waveguides  701  can be configured to output light having a wavefront toward the outcoupler  709 , which can direct the wavefront in a different plane, for example. For example, the plurality of first waveguides  701 A can form light  752 A, and the plurality of second waveguides  701 B can form light  752 B. Similarly, the third plurality of waveguides  701 C can output light  752 C, and the fourth plurality of waveguides can output light  752 D. Although not shown in the figure, each waveguide within a set (e.g., the first plurality of waveguides  701 A) may form a different wavefront, where the different wavefronts may be shifted slightly in output location. 
     Light  752 A, light  752 B, light  752 C, and light  752 D can collectively form light  752 E. In some examples, the distances between adjacent sets of waveguides can be such that light  752 E has a flat (e.g., less curvature than the wavefronts of light  752 A, light  752 B, light  752 C, and light  752 D) wavefront. One or more parameters of the configuration can be adjusted to achieve certain properties for light  752 E. The one or more parameters can include, but are not limited to, the spacing between waveguides within a set (e.g., distance  707 , which can be based on a decorrelation distance), the spacing between sets of waveguides (e.g., distance  708 ), the number of waveguides, the total width of a given set of waveguides (e.g., can be based on the size of the outcoupler  709 ), the width of a waveguide, the dimensions (e.g., length) of the free-propagation region, the waveguide tilt, the waveguide facet tilt, and the waveguide steering. Additionally or alternatively, each waveguide within a set can be configured to output a different range of wavelengths. 
       FIG.  7 B  illustrates an exemplary light emitter configuration having a spherical wavefront including multiple portions pointing in different directions according to examples of the disclosure. The waveguide  701 A can be configured to output light  741 . Light  741  can include a plurality of portions such as portion  741 A, portion  741 B, portion  741 C, portion  741 D, and portion  741 E. The spherical wavefront of each diffracting beam from waveguide  701 A can cause each portion to be directed towards a different direction. For example, the portion  741 A can be directed at a divergence angle of 30° relative to the portion  741 C. The divergence angle may be determined by the waveguide design (e.g., width) and optical wavelength, for example. 
     Multiple waveguides and the corresponding portions of the spherical wavefront pointing in different directions can be combined to form a light emitter capable of emitting light at multiple angles and along multiple locations, as illustrated in  FIG.  7 C . For example, the spherical wavefront of light output by the waveguide  701 A can include a portion  741 B directed at a first angle and towards a first location. The spherical wavefront of light output by the waveguide  701 C can include a portion  743 B directed at the same first angle, but towards a second location, different from the first location. As another example, the spherical wavefront of light output by the waveguide  701 B can include a portion  741 E directed at a second angle and towards a second location. The spherical wavefront of light output by waveguide  701 C can include a portion  743 D directed at the same second location, but at a third angle, different from the second angle. In some examples, the one or more light emitter configurations discussed above can include one or more reflectors (not shown). 
     Noise 
     In some examples, optical measurements can include noise. Noise can take multiple forms including incoherent and coherent. Incoherent noise can be due to diffuse scattering that may occur as light transmits through the sample, and its properties may be independent of the phases of light incident on the detector. In some instances, the sample may be inhomogeneous, where the sample properties may vary across different volumes in the sample. The inhomogeneity of the sample may contribute to incoherent noise through random distributions of diffuse scattering and more. Incoherent noise may also vary depending on wavelength. Coherent noise can be due to, e.g., speckle, and its properties can depend on the phases of light incident on the detector along with the spectral density of the source power. In some architectures, both incoherent and coherent noise may be present and may be with varying percentages. An optical sampling architecture capable of reducing both incoherent and coherent noise may be desired. 
       FIG.  8    illustrates a planar view of an exemplary system interface and sample according to examples of the disclosure.  FIG.  8    may be similar to  FIG.  2    and may illustrate additional components included in the system such as the light emitter, optics, the detector, etc. The system interface  880  can include a launch region  882  and a detection region  856 , where the regions can be configured such that one dimension is elongated relative to the other dimension. For example, the launch region  882  can be rectangular (i.e., a stripe geometry) with the y-dimension being elongated relative to the x-dimension. For example, the launch region  882  can have a length that is multiple factors (e.g., 10, 15, 20, 25, etc.) greater than its width. 
     The light emitter  807  can be configured to generate light  852 , where optics  891  can direct, collimate, focus, and/or magnify light  852 . Optics  891  can include, for example, collimating optics and/or an outcoupler (discussed below). In some examples, light  852  can collectively form a launch sheet light beam  853  (instead of a linear light beam). The launch sheet light beam  853  can be formed by a single light emitter or multiple light emitters. In some examples, the system can be configured (e.g., by including spherical or cylindrical lenses) such that some or all of light  852  can be oriented parallel or within a spreading range (e.g., within ±5°) from each other. 
     The launch sheet light beam  853  can exit the system through the launch region  882 . The angle and position that light  852  exits at the launch region  882  along the x-plane can be referred to as the in-plane launch angle  842  and in-plane launch position  843 , respectively. The angle and position that light  852  exits at the launch region  882  along the y-plane can be referred to as the out-of-plane launch angle and the out-of-plane launch position, respectively (not shown). 
     Light may undergo one or more small-angle scattering events before reaching the location  857 . Light (e.g., light  852 ) included in the launch sheet light beam  853  can undergo a single large-angle scattering event at the location  857  within the measured sample volume  820 . The distribution of light  852  can be along the elongated y-direction. In this manner, light  852  can extend in the y-direction creating a scatter voxel within the measured sample volume  820  at location  857 . The scatter voxel can be the volume within the measured sample volume  820  where the launch sheet light beam  853  intersects with the detection sheet light beam  855 . 
     In some examples, the scatter voxel at location  857  can be longer (e.g., in the y-dimension) than the launch region  882  due to spreading of light  852 . For example, the scatter voxel can be 0.5 mm longer in the y-dimension than the launch region  882 . The spreading may be due to one or more scattering events causing a change in angles of some of the light. Some of light  852  included in the launch sheet light beam  853  can reflect at the location  857  to form light  854 . Light  854  can collectively form at least a portion of the detection sheet light beam  855  (instead of a linear light beam). In some instances, light  854  included in the detection sheet light beam  855  can undergo multiple small-angle scattering events before reaching the detection region  856 . 
     The detection region  856  and/or the optics  894  can constrain or select light in the plane of the detection sheet light beam  855 . The detection sheet light beam  855  can enter the system through the detection region  856 . The detection region  856  can be configured such that one dimension is elongated relative to the other dimensions. The elongated dimension can be the y-dimension, which can be the same elongated dimension as that of the launch region  882 . In some examples, the size and shape of the launch region  882  and the detection region  856  can be the same. In some examples, the detection region  856  can be longer (e.g., in the y-dimension) than the launch region  882  to collect more light that may undergo multiple small-angle scattering events. A detector  830  can receive the detection sheet light beam  855  and can generate one or more signals indicative of the detection sheet light beam  855 . 
     Outcoupler Array Geometry 
     In some instances, optical measurements can include noise. Noise can take multiple forms including incoherent and coherent. Incoherent noise can be due to diffuse scattering that may occur as light transmits through the sample, and its properties may be independent of the phases of light incident on the detector. The correlation may be a property determined by the sample, and may not be an inherent property of the light beams. Properties determined by the sample can include, but are not limited to, decorrelation angles, decorrelation distances, etc. In some instances, the sample may be inhomogeneous, where the sample properties may vary across different volumes in the sample. The inhomogeneity of the sample may contribute to incoherent noise through random distributions of diffuse scattering and the like. Incoherent noise may also vary depending on wavelength. Coherent noise can be due to, e.g., speckle, and its properties can depend on the phases of light incident on the detector along with the spectral density of the source power. In some architectures, both incoherent and coherent noise may be present and may be with varying percentages. 
     One way to reduce incoherent noise can be to sum together multiple, uncorrelated light beams, which can be created by using an outcoupler array.  FIG.  9 A  illustrates a top view of an exemplary integrated photonics chip including an outcoupler array according to examples of the disclosure. The chip  900  can include multiple components including, but not limited to, a multiplexer  911 , a phase control network  913 , and an outcoupler array  914 . The multiplexer  911  can receive light and can be configured to selectively output one or more light rays. In some examples, the multiplexer  911  can be connected to a light emitter and/or phase control network  913  using one or more optical traces. The phase control network  913  (discussed in more detail below) can be configured to receive one or more light rays from the multiplexer  911  and can be configured to control the phase of at least some of the one or more light rays. The phase control network  913  can output light to the outcoupler array  914  using one or more waveguides  910 . 
     The outcoupler array  914  can include a plurality of outcouplers  909 . The outcoupler array  914  can include a high-etendue outcoupler array geometry. The high etendue can include both spatial and angular spreading. The plurality of outcouplers  909  can be configured to redirect received light, which can be light that has propagated through the one or more waveguides  910 . In some instances, the integrated photonics chip can be arranged such that light emitted from the one or more light emitters can propagate through one or more waveguides in one plane (e.g., x-y plane) and can be redirected to another plane (e.g., y-z plane) by the plurality of outcouplers  909 . 
     The outcoupler array  914  can create light beams having multiple different launch positions. One exemplary arrangement for creating different in-plane launch positions can be a staggered arrangement, such as shown in the  FIG.  9 A . The staggered arrangement can include two adjacent outcouplers  909  have different locations (i.e., launch position) along the x-dimension. For example, outcoupler  909 A and outcoupler  909 B may be located in different locations along the x-dimension. As such, the outcoupler  909 A may have a longer waveguide  910 A than the waveguide  910 B coupled to the outcoupler  909 B. The staggered arrangement can include sets of a plurality of staggered outcouplers  909 , where the outcouplers  909  within a set are staggered with respect to the outcouplers  909  included in the same set, as shown in the figure. Examples of the disclosure can include the outcouplers  909  of different sets having the same location in the x-dimension, but different locations in the y-dimension. For example, the outcoupler  909 A can have the same x-dimension as the outcoupler  909 C, but the two outcouplers can be included in different sets. As an example, the figure illustrates the outcoupler array  914  as including eight sets, each set having four outcouplers  909 . 
       FIGS.  9 B- 9 C  illustrate top and cross-sectional views, respectively, of an exemplary outcoupler and waveguide according to examples of the disclosure. The waveguide  910  can be configured to propagate light  941  emitted by one or more light emitters in one plane. Light  941  can exit the waveguide  910  at a termination point and can be incident on a reflecting surface of the outcoupler  909 . The outcoupler  909  can redirect light  941  to another plane towards, e.g., the system interface (e.g., system interface  880  illustrated in  FIG.  8   ). One or more of the plurality of outcouplers  909  can have a region  915 . The region  915  can be an area of the chip  900  where other components, such as other outcouplers  909 , waveguides  910 , etc., may be excluded. 
     The one or more waveguides  910  can have a minimum spacing. Referring back to  FIG.  9 A , the spacing between the center of adjacent waveguides can be x-spacing  915 X, for example. The spacing between the centers of two adjacent waveguides having the same x-location (e.g., same column) can be referred to as y-spacing  915 Y. In some instances, at least one region  915  may have a separation distance, along one or both dimensions (e.g., x- and y-dimensions), equal to the minimum required spacing between waveguides  910 . Examples of the disclosure can include a separation distance of the launch positions being more than the correlation length of position-dependent scattering variations (e.g., coherent or incoherent noise) sources within the sample. 
     In some examples, the outcoupler array can be arranged as a two-sided array.  FIG.  10    illustrates a top view of an exemplary integrated photonics chip including a two-sided outcoupler array according to examples of the disclosure. The chip  1000  can include multiple components such as a multiplexer  1011  and a phase control network  1013 . The multiplexer  1011  and the phase control network  1013  can be similar in function and/or structure as the multiplexer  911  and the phase control network  913  described above with respect to  FIG.  9 A . 
     The chip  1000  can also include an outcoupler array  1014 , which can include a plurality of outcouplers  1009 , and one or more waveguides  1010 . The one or more waveguides  1010  can include one or more termination points  1012 . The plurality of outcouplers  1009 A, associated waveguides  1010 A, and associated light  1041 A can be located on one side (e.g., the left side). The plurality of outcouplers  1009 B, associated waveguides  1010 B, and associated light  1041 B can be located on another side (e.g., the right side). The outcouplers and waveguides of a given side can be oriented such that light from one side (e.g., light  1041 A) propagates in a different (e.g., opposite) direction than light from another side (e.g., light  1041 B). Corresponding components can be similarly situated. For example, the plurality of outcouplers  1009 A can have one or more reflecting surfaces that face the left side, whereas the plurality of outcouplers  1009 B can have one or more reflecting surfaces that face the right side. 
     Examples of the disclosure can further include arranging the outcouplers and waveguides in a staggered arrangement, having a certain spacing (e.g., based on minimum spacing between waveguides), and the like. In this manner, by arranging the outcoupler array in a two-sided geometry, the density of the outcouplers can be increased and/or the footprint size of the outcoupler array can be decreased. Although the figure illustrates two-sided geometry, examples of the disclosure can include any number of sides for an arrangement such as three-sided or four-sided. In some examples, the outcoupler may be capable of creating a high etendue launch beam while controlling the path length distribution. 
     Launch Regions 
     Another way to reduce incoherent noise can be to create light beams having multiple different in-plane launch angles. In some examples, the in-plane launch angles can be separated (i.e., have a non-zero difference) by angles greater than the correlation angle in the x-dimension. The outcoupler can also create light beams having multiple different out-of-plane launch angles, which may, e.g., be separated by angles greater than the correction angle in the y-dimension. 
       FIG.  11    illustrates a cross-sectional view of an exemplary integrated photonics chip including a plurality of emissions regions according to examples of the disclosure. The device  1100  can include a detection region  1156 , optics  1194 , optics  1191 , a light emitter  1107 , and a detector  1130  that can be similar to correspondingly labeled elements from the other figures. The device  1100  can further include multiple launch regions  1182 . Although the figure illustrates two launch regions  1182  that are spatially separated, examples of the disclosure can include a single continuous launch region. 
     The light emitter(s)  1107  can emit light  1141 . Light  1141  may be split into a plurality of light beams, such as light  1141 A and light  1141 B, by a splitter  1144 . The splitter  1144  may be configured to split the light in any proportion, such as half of light  1141  to light  1141 A and the other half to light  1141 B; examples can include other proportions. In some examples, light  1141 A and light  1141 B may be incoherent. 
     The plurality of light beams  1141  may be incident on optics  1191 . The optics  1191  can include multiple lenses or other types of optics. For example, light  1141 A can be incident on optics  1191 A, and light  1141 B can be incident on optics  1191 B. As shown in the figure, light  1141 A may interrogate the same location of the measured sample volume  1120  as light  1141 B, where the light beams may be uncorrelated. In some instances, light  1141 A and light  1141 B may intersect at a location  1121 B. The location  1121 A and the location  1121 C can be scattering sites, in some examples. A portion of the light beam(s) may return to the system interface  1180 . Light  1141 A and light  1141 B may also have other scattering sites where light (e.g., light  1141 C, light  1141 D, light  1141 E) can return to the system interface  1180  to be measured by the detector  1130 . 
     Detection Regions 
     The device can also include multiple detection regions.  FIG.  12    illustrates a cross-sectional view of an exemplary integrated photonics chip including a plurality of detection regions according to examples of the disclosure. The device  1200  can include a launch region  1282 , optics  1294 , optics  1291 , a light emitter  1207 , and detectors  1230  that can be similar to correspondingly labeled elements from the other figures. The device  1200  can further include multiple detection regions  1256  and multiple optics  1294 A and  1294 B. Although the figure illustrates two detection regions  1282  that are spatially separated, examples of the disclosure can include a single continuous detection region. 
     The light emitter  1207  can emit light  1241  towards optics  1291 . After optics  1291 , light  1241  can exit the device  1200  at the launch region  1282 . In some instances, light  1241  may interrogate a different location of the measured sample volume  1220 . For example, light received by optics  1294 A and detector  1230 A can be return light from location  1221 A, and light received by optics  1294 B and detector  1230 B can be return light from location  1221 B. The detector  1230 A and the detector  1230 B can be spatially distinct, so the associated noise can be incoherent and uncorrelated. 
     Optics 
     The properties of one or more optics can be configured such that they increase the etendue, as illustrated in the cross-sectional view of an exemplary integrated photonics device of  FIG.  13   . The device  1300  can include a detection region  1356 , optics  1394 , a light emitter  1307 , and a detector  1330  that can be similar to correspondingly labeled elements from the other figures. 
     The device  1300  can also include the optics  1391 A and optics  1391 B. The optics  1391 A can include one or more functions and/or characteristics similar to optics  191 , optics  291 , optics  591 , and optics  691  discussed above. The optics  1391 B (i.e., divergence optics) can be configured to change the angles of light  1341  to create divergence, thereby increasing the etendue. For example, the optics  1391 B can include a diverging lens, a diffuser, etc. The change in angles can allow light  1341  to interrogate multiple locations, at location  1321 A and location  1321 B, of the measured sample volume  1320 . The return light, from location  1321 A and location  1321 B, can travel through system interface  1380  and optics  1394  to detector  1330 . In some examples, the device  1300  can be configured such that optics  1391 B can expand the angles of light  1341  along the x-plane at the system interface  1380  and/or interface of the measured sample volume  1320 . The device  1300  can also be configured such that the angles of light  1341  can be de-cohered along the y-plane before light  1341  reaches the system interface  1380 . 
     Phase Control Network 
     A group delay network can be used to make multiple light emitters incoherent. Examples of the disclosure can include an interleaved group delay network and a direct phase control network, each discussed in more detail below. In some examples, the group delay network can be configured such that the frequency bandwidth can be inversely related to the length delay between outcouplers (e.g., outcouplers  909  illustrated in  FIG.  9 A ). 
       FIG.  14    illustrates a block diagram of an exemplary phase control network using an interleaved group delay according to examples of the disclosure. Phase control network  1413  can include an input  1417 , which can be an optical signal received from a multiplexer (e.g., multiplexer  911  illustrated in  FIG.  9 A , multiplexer  1011  illustrated in  FIG.  10   , etc.). The phase control network  1413  can include a plurality of splitters  1444  and a plurality of group delays, such as group delay  1445 A, group delay  1445 B, and group delay  1445 C. The plurality of splitters  1444  can be interleaved with the plurality of group delays  1445 . Although the figure illustrates a plurality of group delays, examples of the disclosure can include a phase control network including a plurality phase shifters. 
     The plurality of splitters  1444  can split the input into multiple (e.g., two) outputs. In some instances, the plurality of splitter  1444  can be optical splitters. At least two of the plurality of group delays  1445  can introduce different group delays. For example, the group delay  1445 A can introduce a 4× group delay, the group delays  1445 B can introduce a 2× group delay, and the group delays  1445 C can introduce a 1× group delay. In this manner, the phase control network  1413  can receive a first number (e.g., one) of inputs and can create a second number (e.g., eight) of outputs from the inputs, where at least two of the outputs can have different group delays. As one example, as shown in the figure, the outputs  1418  can each have different delays. Output  1418 A can have no change in delay, output  1418 B can have 1× change in delay, output  1418 C can have 2× change in delay, output  1418 D can have 3× change in delay, output  1418 E can have 4× change in delay, output  1418 F can have 5× change in delay, output  1418 G can have a 6× change in delay, and output  1418 H can have a 7× change in delay. The plurality of outputs  1418  can be inputs to a plurality of waveguides (e.g., waveguides  910  illustrated in  FIG.  9 A ). The plurality of outcouplers (e.g., outcouplers  909  illustrated in  FIG.  9 A ) of the outcoupler array can then receive light having different group delays that originated from the same light emitter. 
       FIG.  15    illustrates a block diagram of an exemplary direct phase control network according to examples of the disclosure. Phase control network  1513  can include an input  1517 , which can be an optical signal received from a multiplexer (e.g., multiplexer  911  illustrated in  FIG.  9 A , multiplexer  1011  illustrated in  FIG.  10   , etc.). The optical signals input to the multiplexer can be output from one or more tunable light sources. The phase control network  1513  can include a plurality of splitters  1544  and a plurality of group delays  1545 . 
     The plurality of splitters  1544  can split an input into multiple (e.g., two) outputs. At least one (e.g., each) of the plurality of group delays  1545  can have a one-to-one correspondence with an output  1518 . In some examples, at least two (e.g., each) of the plurality of group delays  1545  can introduce different group delays. As one example, each of the plurality of group delays  1545  can introduce a different group delay than another group delay  1545  within the same set of outputs  1518 . In this manner, the plurality of outcouplers (e.g., outcouplers  909  illustrated in  FIG.  9 A ) of the outcoupler array can then receive light having different group delays that originated from the same light emitter. 
     Examples of the disclosure can include have multiple sets of outputs, where at least two sets can be coupled to different phase control networks. Examples of the disclosure can also include one output that does not have a phase shifter located at the output of the splitter. 
     Alternatively, in some examples, the phase control network can be configured with an active phase shifter coupled to each output  1518 . 
     Combined Outcoupler Array and Phase Control Network 
     Examples of the disclosure can include using the phase control network for multiple outcoupler arrays.  FIG.  16    illustrates an exemplary integrated photonics chip including outputs from a phase control network used for multiple outcoupler arrays according to examples of the disclosure. The chip  1600  can include a multiplexer  1611 , a phase control network  1613 , and a plurality of outcoupler arrays  1614  that can be similar to correspondingly labeled elements from the other figures. 
     The outcoupler array  1614 A can be associated with different locations of the measured sample volume (e.g., measured sample volume  820  illustrated in  FIG.  8   ) and detector (e.g., detector  830  illustrated in  FIG.  8   ) than the outcoupler array  1614 B. As a result, the signals from the different outcoupler arrays can be incoherent and uncorrelated. In some examples, since the signals are incoherent and uncorrelated, the same phase control network  1613  can be used for multiple (e.g., both) outcoupler arrays. The chip  1600  can include a plurality of splitters  1644  to allow sharing of the outputs from the same phase control network  1613 . 
     In some instances, an outcoupler array can include multiple zones, such as when the device is configured to have a launch sheet light beam with a larger amount of elongation in the y-dimension. Light from the multiple zones can be spatially aggregated to create the launch sheet light beam.  FIG.  17    illustrates an exemplary integrated photonics chip including outputs from a phase control network used for outcoupler arrays including multiple zones according to examples of the disclosure. The chip  1700  can include a multiplexer  1711 , a phase control network  1713 , and a plurality of splitters  1744  that can be similar to correspondingly labeled elements from the other figures. 
     A plurality of splitters  1744 B can split the same outputs from the phase control network  1713  to different zones of the same outcoupler array  1714 . At least one of the outcoupler arrays  1714  can be include multiple zones. For example, outcoupler array  1714  can include zone  1719 A and zone  1719 B. The zone  1719 A can be associated with a first location of the measured sample volume, such as the location associated with light  1141 A and optics  1191 A of  FIG.  11   . The zone  1719 B can be associated with a second location of the measured sample volume, such as the location associated with light  1141 B and optics  1191 B of  FIG.  11   . That is, the same outcoupler array can be used to send light having different properties (e.g., launch angle). 
     In some instances, the different zones associated with a given outcoupler array can be associated with different regions (e.g., pixels) of a detector. The signals received by the different regions of the detector can be incoherent and uncorrelated. Examples of the disclosure can further include using one or more additional group delays (not shown) to change the group delay within a zone. The additional group delay can be used to reduce coherent noise. 
     In some examples, the zones can be optimized with a certain size. The size may be related to a point spread function of the system. The point spread function may represent the properties (e.g., size and shape) of the light beam caused by diffraction, where the properties may be determined based on the scattering properties within the sample. 
     Operation of the Integrated Photonics Device 
     The operation of the integrated photonics device will be described.  FIG.  18    illustrates an exemplary process flow for measuring sample properties using an integrated photonics device having an optical sampling architecture according to examples of the disclosure. One or more light emitters (e.g., light emitter  807  illustrated in  FIG.  8   ) can generate light towards one or more multiplexers (step  1852  of process  1850 ). One or more multiplexers (e.g., multiplexer  911  illustrated in  FIG.  9 A ) can receive light from one or more light emitters and can selectively output one or more light rays to a phase control network (e.g., phase control network  913  illustrated in  FIG.  9 A ) (step  1854  of process  1850 ). 
     The phase control network can introduce one or more delays in the light ray(s) (e.g., light  941  illustrated in  FIGS.  9 B- 9 C ) (step  1856  of process  1850 ). In some examples, the delays can include fixed group delays where the light emitter(s) is a tunable light source. In other examples, the light emitter(s) may emit light of a fixed wavelength, and the phase can be actively controlled via, e.g., sequencing through multiple phase states of the outputs of the phase control network. 
     The light rays can propagate through one or more waveguides (e.g., waveguides  910  illustrated in  FIG.  9 A ) to one or more outcoupler arrays (e.g., outcoupler array  914  illustrated in  FIG.  9 A ) (step  1858  of process  1850 ). In some examples, one or more splitters (e.g., splitters  1644  illustrated in  FIG.  16   ) can split and/or direct the light rays to different outcoupler arrays and/or zones (e.g., zone  1719 A illustrated in  FIG.  17   ) within the same outcoupler array. The outcouplers included in the outcoupler array(s) can redirect the light (step  1860  of process  1850 ). 
     The light rays can exit the device through one or more launch regions (e.g., launch region  882  illustrated in  FIG.  8   ) (step  1862  of process  1850 ). The light rays can undergo one or more scattering events in the measured sample volume and can return to one or more detection regions (e.g., detection region  856  illustrated in  FIG.  8   ) of the device (step  1864  of process  1850 ). The detection region and/or one or more components can select, direct, and/or focus the light towards one or more detectors (step  1866  of process  1850 ). The detector(s) can receive the light and generate one or more signals indicative of the properties of the received light (step  1868  of process  1850 ). A processor can receive the signal(s) and determine the sample properties using the signal(s) (step  1870  of process  1850 ). 
     One or more of the functions described above can be performed, for example, by firmware stored in memory and executed by a processor or controller. The firmware can also be stored and/or transported within any non-transitory computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “non-transitory computer-readable storage medium” can be any medium (excluding a signal) that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The non-transitory computer readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc such as a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory such as compact flash cards, secured digital cards, USB memory devices, memory sticks and the like. In the context of this document, a “transport medium” can be any medium that can communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The transport readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, or infrared wired or wireless propagation medium. 
     A system is disclosed. The system can comprise: at least one light emitter that emits light; a system interface including: a launch region from which the light emitted by the at least one light emitter is capable of exiting the system, wherein the launch region includes a first dimension and a second dimension, the second dimension of the launch region is elongated relative to the first dimension of the launch region, wherein the launch region is configured to form, from the light emitted by the at least one light emitter, a first light beam having a second dimension that is elongated relative to a first dimension of the first light beam as the first light beam exits the system, and a detection region through which light is capable of entering the system, wherein the detection region includes a first dimension and a second dimension, the second dimension of the detection region elongated relative to the first dimension of the detection region, wherein the second dimension of the launch region is elongated along a same direction that the second dimension of the detection region is elongated, and wherein the detection region is configured to form, from the light entering the system, a second light beam within the system, the second light beam having a second dimension that is elongated relative to a first dimension of the second light beam; a detector that detects at least a portion of the second light beam and generates one or more signals indicative of the portion of the second light beam; and logic that determines one or more sample properties from the one or more signals. Additionally or alternatively, in some examples, a size and a shape of the launch region is same as a size and a shape of the detection region. Additionally or alternatively, in some examples, the second dimension of the detection region is longer than the second dimension of the launch region. Additionally or alternatively, in some examples, the system further comprises: optics selectively allowing the portion of the second light beam to pass through to the detector, wherein the portion of the second light beam meets a change in angle criteria. Additionally or alternatively, in some examples, the change in angle criteria includes a threshold range of angles based on a targeted optical path length. Additionally or alternatively, in some examples, the detection region forms the second light beam by selectively allowing light, from the light entering the system, that meets a change in angle criteria. Additionally or alternatively, in some examples, the at least one light emitter includes one or more outcouplers and a reflector, the one or more outcouplers located a first separation distance from the reflector, wherein the one or more outcouplers are located a second separation distance from the launch region, wherein the detector is located a third separation distance from the detection region, and wherein a total of a targeted optical path length, the first separation distance, the second separation distance, and the third separation distance are equal to a focal length of the reflector. Additionally or alternatively, in some examples, the system further comprises: a multiplexer that: receives the light emitted by the at least one light emitter, forms, from the light emitted by the at least one light emitter, a third light beam, and outputs the third light beam; a phase control network that: receives the third light beam, and controls a phase of at least a portion of the third light beam; and an outcoupler array including a plurality of outcouplers, the outcoupler array redirecting the third light beam to the launch region. Additionally or alternatively, in some examples, the third light beam has one or more of: different in-plane launch angles and in-plane launch locations. 
     A light emitter is disclosed. The light emitter can comprise: one or more light sources that emit light along a first plane; one or more waveguides that output the light emitted by the one or more light sources; and one or more outcouplers that direct the light, output by the one or more waveguides, to a second plane, wherein the light directed by the one or more outcouplers is a first light beam having different properties relative to the light output by the one or more waveguides, the properties including in-plane launch angles, in-plane launch locations, or both; wherein the first light beam has a second dimension that is elongated relative to a first dimension of the first light beam. Additionally or alternatively, in some examples, the light emitter further comprises: one or more reflectors receiving the light emitted by the one or more light sources and directing the light emitted by the one or more light sources along the first plane to the one or more outcouplers, wherein the one or more reflectors include a first location and a second location, wherein the one or more outcouplers include a first location and a second location; wherein a first portion of the light emitted by the one or more light sources is incident at the first location of the reflector and the first location of the one or more outcouplers, and wherein a second portion of the light emitted by the one or more light sources is incident at the second location of the reflector and the second location of the one or more outcouplers. Additionally or alternatively, in some examples, the one or more waveguides include: a first waveguide that outputs the first portion of the light emitted by the one or more light sources, and a second waveguide that outputs the second portion of the light emitted by the one or more light sources, wherein the first location of the one or more outcouplers and the second location of the one or more outcouplers are different. Additionally or alternatively, in some examples, the one or more waveguides include: a first waveguide that outputs the first portion of the light emitted by the one or more light sources, and a second waveguide that outputs the second portion of the light emitted by the one or more light sources, wherein the first location of the one or more outcouplers and the second location of the one or more outcouplers are the same, and the first portion of the light emitted by the one or more light sources and the second portion of the light emitted by the one or more light sources have different angles. Additionally or alternatively, in some examples, a separation distance between at least one of the one or more waveguides and at least one of the one or more reflectors is equal to a focal length of the at least one of the one or more reflectors. Additionally or alternatively, in some examples, the one or more waveguides include: a splitter that receives and splits the light outputted by the one or more waveguides into a plurality of light rays; a plurality of optical attenuators that: receive the plurality of light rays, and block or allow at least some of the plurality of light rays. Additionally or alternatively, in some examples, the one or more waveguides include at least two waveguides located such that facets of the at least two waveguides have different angles with respect to the one or more outcouplers. Additionally or alternatively, in some examples, the one or more waveguides include a first plurality of waveguides and a second plurality of waveguides, wherein the first plurality of waveguides are located such that facets of the first plurality of waveguides have an angle with respect to the one or more outcouplers different than facets of the second plurality of waveguides. 
     A method for using a system is disclosed. The method can comprise: emitting light using at least one light emitter; forming a first light beam from the light emitted by the at least one light emitter using a launch region, wherein the launch region includes a first dimension and a second dimension, the second dimension of the launch region is elongated relative to the first dimension of the launch region; allowing the first light beam to exit the system through the launch region, wherein the first light beam has a second dimension that is elongated relative to a first dimension of the first light beam as the first light beam exits the system; allowing light to enter through the system through a detection region, wherein the detection region includes a first dimension and a second dimension, the second dimension of the detection region elongated relative to the first dimension of the detection region, wherein the second dimension of the launch region is elongated along a same direction that the second dimension of the detection region is elongated; forming a second light beam from the light entering the system using the detection region, wherein the second light beam has a second dimension that is elongated relative to a first dimension of the second light beam; detecting at least a portion of the second light beam by a detector; generating one or more signals indicative of the portion of the second light beam detected by the detector; and determining one or more sample properties from the one or more signals. Additionally or alternatively, in some examples, forming the first light beam includes selectively controlling one or more parameters of the light emitted by the at least one light emitter. Additionally or alternatively, in some examples, forming the second light beam includes selectively controlling one or more parameters of the light that has entered through the system using optics. 
     Although the disclosed examples have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosed examples as defined by the appended claims.

Metadata:
Filing Date: 20180927
Publication Date: 20230214
Grant Date: 20230214
Priority Date: 20170929
Inventors: ARBORE, Mark Alan
TERREL, MATTHEW A.
Pele, Jason
Assignee: APPLE INC
CPC Classifications: [{"code": "G01N21/01", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01N2021/4711", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01N2021/4711", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01N2201/068", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01N2201/066", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01N21/49", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01N2201/066", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01N21/49", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01N2021/4711", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01N2201/068", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01N2201/066", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01N21/49", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01N21/49", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01N21/01", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 63896649