A Raman sensor includes a light source assembly having a plurality of light sources configured to emit light to a plurality of skin points of skin, each of the plurality of skin points having a predetermined separation distance from a light collection region of the skin from which Raman scattered light is collected; a light collector configured to collect the Raman scattered light from the light collection region of the skin; and a detector configured to detect the collected Raman scattered light.

Optical property measurement using a sensor behind a display screen Examples of this application disclose a method for measuring optical properties of a target. The method comprises illuminating the target with an illumination area with a display screen in contact with the target, and analysing signals reflected from the target and transmitted back through the display screen to a sensor positioned behind the display screen, to determine the optical properties of the target.

Disclosed herein is an all-digital phase and timing correction procedure for coherent averaging in dual-comb and multiheterodyne spectroscopy—applicable to any dual-comb spectroscopy setup. It can account for large frequency/phase instabilities of the used sources, yielding a significant reduction of the noise pedestal and an increase in signal-to-noise ratio (SNR) of the radio frequency (RF) beat notes. This technique is computationally efficient and can be conveniently implemented either as a post-processing algorithm or in a real-time data acquisition and processing platform without the necessity of adding any additional optical elements to the dual-comb spectroscopy system. By implementing this technique, the performance of any comb- or comb-like-source-based DCS system with a sufficient degree of mutual coherence between the optical modes can be improved in terms of SNR and number of spectroscopically-usable RF beat notes. The described technique is compatible with a DC-centered RF spectrum, where the negative frequencies are folded to the positive domain to double the number of beat notes within the detector bandwidth. The technique enables coherent averaging over extended time-scales even for free-running combs, thus increasing the sensitivity of absorption and dispersion DCS measurements.

Systems and methods for measuring temperature in an environment by creating a first beam having an energy of about 50 mJ/pulse, and a pulse duration of about 100 ps. A second beam is also created, having an energy of about 2.3 mJ/pulse, and a pulse duration of about 58 ps. The first beam and the second beam are directed into a probe region, thereby expressing an optical output. Properties of the optical output are measured at a sampling rate of at least about 100 kHz, and temperature measurements are derived from the measured properties of the optical output. Such systems and methods can be used to measure temperature in environments exhibiting highly turbulent and transient flow dynamics.

Described herein are optical sensing devices for photonic integrated circuits (PICs). A PIC may comprise a plurality of waveguides formed in a silicon on insulator (SOI) substrate, and a plurality of heterogeneous lasers, each laser formed from a silicon material of the SOI substrate and to emit an output wavelength comprising an infrared wavelength. Each of these lasers may comprise a resonant cavity included in one of the plurality of waveguides, and a gain material comprising a non-silicon material and adiabatically coupled to the respective waveguide. A light directing element may direct outputs of the plurality of heterogeneous lasers from the PIC towards an object, and one or more detectors may detect light from the plurality of heterogeneous lasers reflected from or transmitted through the object.

A surgical visualization feedback system is disclosed. The surgical visualization feedback system comprises an emitter assembly configured to emit electromagnetic radiation toward an anatomical structure. The emitter assembly comprises a structured light emitter configured to emit a structured light pattern on a surface of the anatomical structure and a spectral light emitter configured to emit spectral light capable of penetrating the anatomical structure. The surgical visualization feedback system further comprises a waveform sensor assembly configured to detect reflected electromagnetic radiation corresponding to the emitted electromagnetic radiation and a control circuit in signal communication with the waveform sensor assembly. The control circuit is configured to receive an input corresponding to a selected surgical procedure, determine an identity of a targeted structure within the anatomical structure based on the selected surgical procedure and the reflected electromagnetic radiation, and confirm the determined identity of the targeted structure through a user input.

Provided is a spectrum processing apparatus for removing noise, caused by a change in temperature, from a spectrum. The spectrum processing apparatus includes: a temperature modulator configured to perform modulation of a temperature of an object; a spectrometer configured to obtain a first spectrum based on the temperature of the object that is changed by the modulation; and a spectrum processor configured to extract a temperature change vector based on the first spectrum, and to correct a second spectrum based on the extracted temperature change vector.

A measurement system is provided with an array of laser diodes with one or more Bragg reflectors. At least a portion of the light generated by the array is configured to penetrate tissue comprising skin. A detection system configured to: measure a phase shift, and a time-of-flight, of at least a portion of the light from the array of laser diodes reflected from the tissue relative to the portion of the light generated by the array; generate one or more images of the tissue; detect oxy- or deoxy-hemoglobin in the tissue; non-invasively measure blood in blood vessels within or below a dermis layer within the skin; measure one or more physiological parameters based at least in part on the non-invasively measured blood; and measure a variation in the blood or physiological parameter over a period of time.

Systems, methods, and devices for fluorescence imaging with a minimal area image sensor are disclosed. A system includes an emitter for emitting pulses of electromagnetic radiation and an image sensor comprising a pixel array for sensing reflected electromagnetic radiation, wherein the pixel array comprises active pixels and optical black pixels. The system includes a black clamp providing offset control for data generated by the pixel array and a controller comprising a processor in electrical communication with the image sensor and the emitter. The system is such that at least a portion of the pulses of electromagnetic radiation emitted by the emitter comprises electromagnetic radiation having a wavelength from about 770 nm to about 790 nm.

Apparatus and methods are described for use with feces of a subject that are disposed within a toilet bowl. One or more light sensors receive light from the toilet bowl, while the feces are disposed within the toilet bowl. A computer processor detects a set of three or more spectral components that have a characteristic relationship with each other in a light spectrum of bile, by analyzing the received light, and detects a presence of bile within the feces, in response to detecting the set of three or more spectral components. The computer processor generates an output in response thereto. Other applications are also described.