Abstract: An exemplary stacked photodetector assembly includes a first wafer and a second wafer bonded to the first wafer. The first wafer includes a SPAD and has a thickness T1 configured to minimize absorption by the first wafer of photons included in light incident upon the first wafer while the SPAD is in a disarmed state. The second wafer has a thickness T2 configured to provide structural support for the first wafer. The stacked photodetector assembly includes a fast gating circuit electrically coupled to the SPAD and configured to arm and disarm the SPAD.

Abstract: An optical measurement system comprises an optical source assembly configured for intensity modulating sample light at multiple frequencies within a frequency range, and delivering the intensity modulated sample light along an optical path of an anatomical structure during a single measurement period, such that the intensity modulated sample light is scattered by the anatomical structure, resulting in signal light that exits the anatomical structure. The optical measurement system further comprises an optical detection assembly configured for detecting the signal light over the frequency range within the measurement period. The optical measurement system further comprises a processor configured for analyzing the detected signal light, and, based on this analysis, determining an occurrence and spatial depth of a physiological event in the anatomical structure.

Abstract: A non-invasive optical measurement system comprises a two-dimensional array of photonic integrated circuits (PICs) mechanically coupled to each other. Each PIC is configured for emitting sample light into an anatomical structure, such that the sample light is scattered by the anatomical structure, resulting in physiological-encoded signal light that exits the anatomical structure. Each PIC is further configured for detecting the signal light. The non-invasive optical measurement system further comprises processing circuitry configured for analyzing the detected signal light from each of the PICs, and based on this analysis, determining an occurrence and a three-dimensional spatial location of the physiological event in the anatomical structure.

Abstract: A non-invasive optical measurement system comprises an optical source for generating source light, and an interferometer for splitting the source light into sample light and reference light, delivering the sample light into an anatomical structure, resulting in physiological-encoded signal light that exits the anatomical structure, and combining the signal light and the reference light into at least three phase-modulated interference light patterns. The optical path lengths of the respective source light and sample light match within a coherence length of the source light.

Abstract: In a non-invasive optical detection system and method, sample light is delivered into a scattering medium. A first portion of the sample light passing through a volume of interest exits the scattering medium as signal light, and a second portion of the sample light passing through a volume of non-interest exits the scattering medium as background light that is combined with the signal light to create a sample light pattern. Reference light is combined with the sample light pattern to create an interference light pattern having a holographic beat component. Ultrasound is emitted into the volume of non-interest in a manner that decorrelates the background light of the sample light pattern from the holographic beat component. The holographic beat component is detected during the measurement period. An optical parameter of the volume of interest is determined based on the detected holographic beat component.

Abstract: An optical measurement system comprises an optical source configured for generating source light having an optical wavelength spectrum. The optical measurement system compises an interferometer configured for splitting the source light into sample light and reference light. The interferometer is further configured for delivering the sample light into an anatomical structure, such that the sample light is scattered by the anatomical structure, resulting in physiological-encoded signal light that exits the anatomical structure. The interferometer is further configured for combining the signal light and the reference light into interference light having the optical wavelength spectrum encoded with depths of the anatomical structure. The optical measurement system further comprises a dispersive spectrometer configured for generating an optical wavelength spectrum-intensity profile from the interference light.

Abstract: An optical source sweeps a source light over an optical wavelength range. An interferometer splits the source light into sample light and reference light, delivers the sample light into an anatomical structure, such that the sample light is scattered by the anatomical structure, resulting in physiological-encoded signal light that exits the anatomical structure, and combines the signal light and the reference light into an interference light pattern having an array of spatial components and a plurality of oscillation frequency components. An optical detector array detects intensity values of the array of spatial components.

Abstract: A non-invasive optical detection system and method are provided. Sample light is delivered into a target volume of interest, whereby the sample light is scattered by the target volume of interest, resulting in a sample light pattern that exits the anatomical structure. Reference light is combined with the sample light pattern to generate at least one interference light pattern, each of which may have a time varying interference component that integrates to a first value in the absence of the physiological event, and that integrates to a second greater value in the presence of the physiological event. Intensities of spatial components of each interference light pattern are detected during a measurement period. A function of the detected spatial component intensities of the interference light pattern(s) is analyzed, and a presence of the physiological event in the target volume of interest is determined based on the analysis.

Abstract: An exemplary photodetector includes a SPAD and a capacitor. The capacitor is configured to be charged, while the SPAD is in a disarmed state, with a bias voltage by a voltage source. The capacitor is further configured to supply, when the SPAD is put in an armed state, the bias voltage to an output node of the SPAD such that a voltage across the SPAD is greater than a breakdown voltage of the SPAD.

Abstract: A non-invasive system and method. Sample light is delivered into an anatomical structure, such that a portion of the sample light passes through a target voxel comprising brain matter in the head and is scattered by the head as signal light. The signal light is detected, changes in the level of water concentration or relative water concentration of the target voxel are detected based on the detected signal light, and a level of neural activity is determined within the target voxel based on the determined changes level of the water concentration or relative water concentration of the target voxel.

Abstract: A system includes a photodetector array and a processor. The photodetector array includes a plurality of photodetectors and is configured to detect light that exits a body and output a plurality of electronic signals representative of the detected light as a function of time. The processor is configured to sample the electronic signals output by the photodetector array at a plurality of delay times during a predetermined time period to generate a sequence of frames, apply a plurality of temporal-based and spatial-based correlation measurement operations to sample values in each of the frames, generate, based on the application of the temporal-based and spatial-based correlation measurement operations to the sample values in each of the frames, a plurality of spatiotemporal correlation measure values for the light detected by the photodetector array, and include the plurality of spatiotemporal correlation measure values in a correlation map.

Abstract: Sample light is delivered into the anatomical structure having a target voxel, whereby a portion of the sample light passing through the target voxel is scattered by the anatomical structure as signal light, and another portion of the sample light not passing through the target voxel is scattered by the anatomical structure as background light that is combined with the signal light to create a sample light pattern. Reference light is combined with the sample light pattern to generate an interference light pattern, such that the signal light and the reference light are combined in a heterodyne manner. Ultrasound is delivered into the target voxel, such that the signal light is frequency shifted by the ultrasound. The ultrasound and the sample light are pulsed in synchrony at the target voxel, such that at least one pulse of the sample light has a combined duration less than a pulse width of the ultrasound.

Abstract: Disclosed herein are devices and methods for modifying a conventional imager to have functional features similar to that of a lock-in camera. Optical mask devices are configured to be coupled to conventional imager sensors and the configuration of the mask devices can be adjusted to acquire image data in rapid succession. One variation of an optical mask device comprises a substrate comprising a pattern of light-blocking and light-transmitting regions and an attachment structure for coupling the optical mask device to the imager. The substrate is configured to adjust the position of the light-blocking regions and light-transmitting regions relative to the light-sensing region of the imager based on a set of one or more predetermined substrate configurations. In some variations, the mask device and/or the imager sensor may be mechanically moved relative to each other based on the set of one or more predetermined substrate configurations.

Abstract: An exemplary non-invasive wearable brain interface system includes a headgear configured to be worn on a head of the user and a plurality of self-contained photodetector units configured to removably attach to the headgear. The photodetector units each include a plurality of photodetectors configured to detect photons of light after the photons reflect from a target within a brain of the user. The brain interface system further includes a master control unit communicatively coupled to each of the photodetector units by way of a plurality of wires and configured to control the photodetector units, the master control unit comprising an input power port configured to connect to a power cable that provides power from a power source for the master control unit and the photodetector units.

Abstract: A system and method of performing ultrasound modulated optical tomography. Ultrasound is delivered into a target voxel in an anatomical structure, and sample light is delivered into the anatomical structure, whereby a portion of the sample light passing through the target voxel is scattered by the biological tissue as signal light, and a portion of the sample light not passing through the target voxel is scattered by the anatomical structure as background light. The ultrasound and sample light are pulsed in synchrony, such that only the signal light is frequency shifted by the ultrasound. Reference light is combined with the signal light and background light to generate an interference light pattern, which is sequentially modulated to generate a plurality of different interference light patterns. Spatial components of each of the different interference light patterns are simultaneously detected and stored in bins.

Abstract: Described herein are systems and methods for noninvasive functional brain imaging using low-coherence interferometry (e.g., for the purpose of creating a brain computer interface with higher spatiotemporal resolution). One variation of a system and method comprises optical interference components and techniques using a lock-in camera. The system comprises a light source and a processor configured to rapidly phase-shift the reference light beam across a pre-selected set of phase shifts or offsets, to store a set of interference patterns associated with each of these pre-selected phase shifts, and to process these stored interference patterns to compute an estimate of the number of photons traveling between a light source and the lock-in camera detector for which the path length falls within a user-defined path length range.

Abstract: A system and method of performing ultrasound modulated optical tomography. Ultrasound is delivered into a target voxel in an anatomical structure, and sample light is delivered into the anatomical structure, whereby a portion of the sample light passing through the target voxel is scattered by the biological tissue as signal light, and a portion of the sample light not passing through the target voxel is scattered by the anatomical structure as background light. The ultrasound and sample light are pulsed in synchrony, such that only the signal light is frequency shifted by the ultrasound. Multiple pulses of the sample light are delivered into the anatomical structure for each pulse of the ultrasound delivered into the target voxel. Reference light is combined with the signal light and background light to generate an interference light pattern, which is sequentially modulated to generate different interference light patterns, which are detected.

Abstract: A system and method of performing ultrasound modulated optical tomography. Ultrasound is delivered into a target voxel in an anatomical structure, and sample light is delivered into the anatomical structure, whereby a portion of the sample light passing through the target voxel is scattered by the biological tissue as signal light, and a portion of the sample light not passing through the target voxel is scattered by the anatomical structure as background light. The ultrasound and sample light are pulsed in synchrony, such that only the signal light is frequency shifted by the ultrasound. Multiple pulses of the sample light are delivered into the anatomical structure for each pulse of the ultrasound delivered into the target voxel. Reference light is combined with the signal light and background light to generate an interference light pattern, which is sequentially modulated to generate different interference light patterns, which are detected.

Abstract: A system and method of performing ultrasound modulated optical tomography. Ultrasound is delivered into a target voxel in an anatomical structure, and sample light is delivered into the anatomical structure, whereby a portion of the sample light passing through the target voxel is scattered by the biological tissue as signal light, and a portion of the sample light not passing through the target voxel is scattered by the anatomical structure as background light. The ultrasound and sample light are pulsed in synchrony, such that only the signal light is frequency shifted by the ultrasound. Reference light is combined with the signal light and background light to generate an interference light pattern, which is sequentially modulated to generate a plurality of different interference light patterns. Spatial components of each of the different interference light patterns are simultaneously detected and stored in bins.

Abstract: A non-invasive system and method. Sample light is delivered into an anatomical structure, such that a portion of the sample light passes through a target voxel comprising brain matter in the head and is scattered by the head as signal light. The signal light is detected, changes in the level of water concentration or relative water concentration of the target voxel are detected based on the detected signal light, and a level of neural activity is determined within the target voxel based on the determined changes level of the water concentration or relative water concentration of the target voxel.