Abstract: A wearable module for use in an optical measurement system includes a light guide configured to receive a light pulse from a light source and guide signal photons included in the light pulse toward a target within a body of a user, and a light diverter configured to divert reference photons included in the light pulse toward at least one detector configured to detect the reference photons.

Abstract: An optical measurement system includes a wearable device including a support assembly configured to be worn on a body of a user and a wearable assembly supported by the support assembly. The wearable assembly includes a plurality of light sources configured to emit a plurality of light pulses toward a target within the body of the user and a plurality of detectors each configured to receive a set of photons included in a light pulse included in the plurality of light pulses after the set of photons is scattered by the target. A position of the wearable assembly on the support assembly is adjustable.

Abstract: A wearable module for use in an optical measurement system includes a housing including a top surface, a light guide including a distal end portion adapted to protrude from the top surface of the housing, and a spring member configured to bias the distal end portion of the light guide away from the top surface of the housing. The light guide is configured to receive, at the distal end portion, photons from a light pulse scattered by a target within a body of a user and guide the received photons toward a photodetector.

Abstract: An optical measurement system includes a wearable module having at least one time-resolved single photon photodetector configured to detect photons from at least one light pulse after the at least one light pulse is scattered by a target within a body of a user; at least one light guide configured to receive the photons and guide the photons to the at least one photodetector; and a housing that houses both the at least one photodetector and at least a portion of the at least one light guide. The optical measurement system further includes a signal processing circuit configured to determine a temporal distribution of the photons detected by the at least one photodetector and generate a histogram based on the temporal distribution of the photons.

Abstract: An illustrative biopotential measurement system includes a plurality of electrodes each configured to record a different signal included in a plurality of signals representative of electrical activity of a target within a user; a plurality of non-inverting operational amplifier circuits each connected to a different electrode included in the plurality of electrodes and each configured to output a different amplified signal included in a plurality of amplified signals representative of amplified versions of the plurality of signals; and a common-mode feedback circuit configured to measure a common-mode signal between the plurality of amplified signals and provide the common-mode signal to the non-inverting operational amplifier circuits. The non-inverting operational amplifier circuits are configured to use the common-mode signal to generate voltage-divided feedback signals used to generate the plurality of amplified signals.

Abstract: An optical measurement system includes a first wearable module comprising a first source configured to emit a first light pulse sequence comprising a plurality of light pulses and a first plurality of detectors configured to detect photons from the first light pulse sequence. The system further includes a second wearable module comprising a second source configured to emit a second light pulse sequence comprising a plurality of light pulses and that is time interleaved with the first light pulse sequence, and a second plurality of detectors configured to detect photons from the second light pulse sequence. The system further includes a control circuit configured to control light pulses emitted by the sources in accordance with time and/or frequency division multiplexing heuristics.

Abstract: An illustrative multimodal measurement system includes a wearable assembly configured to be worn by a user and comprising a plurality of light sources each configured to emit light directed at a target within the user, a plurality of detectors configured to detect arrival times for photons of the light after the light is scattered by the target, and a plurality of electrodes configured to be external to the user and detect electrical activity of the target.

Abstract: An optical measurement system includes a wearable module assembly configured to be worn on a body of a user. The wearable module assembly includes a plurality of wearable modules and a connecting assembly. Each wearable module includes a light source configured to emit a light pulse toward a target within the body of the user and a plurality of detectors configured to receive photons included in the light pulse after the photons are scattered by the target. The connecting assembly physically and flexibly connects the plurality of wearable modules such that the wearable module assembly is conformable to a three-dimensional (3D) surface of the body of the user when the wearable module assembly is worn on the body of the user.

Abstract: An exemplary system includes an array of photodetectors and a control system. Each photodetector of the array of photodetectors may include a single-photon avalanche diode (SPAD) and a fast-gating circuit configured to arm and disarm the SPAD. The control system is configured to control a current drawn by the array of photodetectors.

Abstract: An illustrative wearable brain interface system includes a headgear configured to be worn on a head of a user and a plurality of photodetector units configured to attach to the headgear, the photodetector units each housing a photodetector included in a plurality of photodetectors configured to be controlled by a master control unit to detect photons of light.

Abstract: The source light having a range of optical wavelengths is split into sample light and reference light. The sample light is delivered into a sample, such that the sample light is scattered by the sample, resulting in signal light that exits the sample. The signal light and the reference light are combined into an interference light pattern having optical modes having oscillation frequency components respectively corresponding to optical pathlengths extending through the sample. Different sets of the optical modes of the interference light pattern are respectively detected, and high-bandwidth analog signals representative of the optical modes of the interference light pattern are output. The high-bandwidth analog signals are parallel processed, and mid-bandwidth digital signals are output. The mid-bandwidth digital signals are processed over an i number of iterations, and a plurality of low-bandwidth digital signals are output on the ith iteration.

Abstract: An exemplary wearable brain interface system includes a headgear configured to be worn on a head of a user, a plurality of photodetector units configured to attach to the headgear, and a master control unit coupled to each of the photodetector units and configured to control the photodetector units by directing a photodetector of each photodetector unit to detect photons of light.

Abstract: An illustrative wearable system includes a head-mountable component configured to be worn on a head of a user and a processor. The head-mountable component includes a time-to-digital converter (TDC) configured to receive, during a predetermined event detection time window that commences in response to an application of a light pulse to a target, a signal triggered by an event in which a photodetector detects a photon of the light pulse after the light pulse reflects from the target, the signal configured to enable a GRO of the TDC. The TDC is further configured to measure, using the GRO, a time interval between when the event occurred and an end of the predetermined event detection time window. The processor is configured to determine, based on the time interval and the predetermined event detection time window, an arrival time of the photon at the photodetector.

Abstract: An exemplary photodetector system includes a photodetector and a time-to-digital converter (TDC) coupled to the photodetector. The TDC is configured to receive, during a predetermined event detection time window that commences in response to an application of a light pulse to a target, a signal triggered by an event in which the photodetector detects a photon of the light pulse after the light pulse reflects from the target. The TDC is further configured to enable, in response to the receiving the signal, a gated ring oscillator (GRO) of the TDC, measure, using the GRO, a time interval between when the event occurred and an end of the predetermined event detection time window, and determine, based on the time interval and the predetermined event detection time window, an arrival time of the photon at the photodetector.

Abstract: An exemplary photodetector system includes a photodetector and a time-to-digital converter (TDC) coupled to the photodetector. The TDC is configured to receive, during a predetermined event detection time window that commences in response to an application of a light pulse to a target, a signal triggered by an event in which the photodetector detects a photon of the light pulse after the light pulse reflects from the target. The TDC is further configured to enable, in response to the receiving the signal, a gated ring oscillator (GRO) of the TDC, measure, using the GRO, a time interval between when the event occurred and an end of the predetermined event detection time window, and determine, based on the time interval and the predetermined event detection time window, an arrival time of the photon at the photodetector.

Abstract: An exemplary system includes an array of photodetectors and a control system. Each photodetector of the array of photodetectors may include a single-photon avalanche diode (SPAD) and a fast-gating circuit configured to arm and disarm the SPAD. The control system is configured to control a current drawn by the array of photodetectors.

Abstract: A wearable system includes a stacked photodetector assembly including a first wafer including a single photon avalanche diode (SPAD), the first wafer having 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, and a second wafer having a thickness T2 including a fast gating circuit electrically coupled to the SPAD and configured to arm and disarm the SPAD, the second wafer bonded to the first wafer in a stacked configuration. The fast gating circuit includes a capacitor configured to be charged, while the SPAD is in the disarmed state, with a bias voltage by a voltage source, and supply, while the SPAD is in an armed state, the bias voltage to the SPAD such that a voltage across the SPAD is greater than a breakdown voltage of the SPAD.

Abstract: An apparatus has a beam steerable laser emitter and a detector array with array elements. Electronics selectively enable first array elements corresponding to expected return signal paths and disable second array elements corresponding to unexpected return signal paths.

Abstract: An exemplary photodetector system includes a plurality of photodetectors connected in parallel and a processor communicatively coupled to the plurality of photodetectors. The processor is configured to receive an accumulated output from the plurality of photodetectors. The accumulated output represents an accumulation of respective outputs from each of the plurality of photodetectors detecting photons during a predetermined measurement time period that occurs in response to a light pulse being directed toward a target within a body. The processor is further configured to determine, based on the accumulated output, a temporal distribution of photons detected by the plurality of photodetectors, and generate, based on the temporal distribution of photons, a histogram representing a light pulse response of the target within the body.

Abstract: The source light having a range of optical wavelengths is split into sample light and reference light. The sample light is delivered into a sample, such that the sample light is scattered by the sample, resulting in signal light that exits the sample. The signal light and the reference light are combined into an interference light pattern having optical modes having oscillation frequency components respectively corresponding to optical pathlengths extending through the sample. Different sets of the optical modes of the interference light pattern are respectively detected, and high-bandwidth analog signals representative of the optical modes of the interference light pattern are output. The high-bandwidth analog signals are parallel processed, and mid-bandwidth digital signals are output. The mid-bandwidth digital signals are processed over an i number of iterations, and a plurality of low-bandwidth digital signals are output on the ith iteration.