A quantum absorption spectroscopy system (100) includes a laser light source (1), a quantum optical system (201), a photodetector (31), and a controller (4). The laser light source (1) emits pump light. The quantum optical system (201) includes a nonlinear optical crystal (23) that generates a quantum entangled photon pair of a signal photon and an idler photon by irradiation with pump light, and a moving mirror (25) that changes a phase of the idler photon, and causes quantum interference between a plurality of physical processes in which the quantum entangled photon pair is generated. The photodetector (31) detects the signal photon when the phase of the idler photon is changed by the nonlinear optical crystal (23) in a state where a sample is disposed on an optical path of the idler photon, and outputs a quantum interference signal corresponding to the detected number of photons. The controller (4) calculates an absorption spectroscopy characteristic of the sample by performing Fourier transform on the quantum interference signal.

Modulation-encoded light, using different spectral bin coded light components, can illuminate a stationary or moving (relative) target object or scene. Response signal processing can use information about the respective different time-varying modulation functions, to decode to recover information about a respective response parameter affected by the target object or scene. Electrical or optical modulation encoding can be used. LED-based spectroscopic analysis of a composition of a target (e.g., SpO2, glucose, etc.) can be performed; such can optionally include decoding of encoded optical modulation functions. Baffles or apertures or optics can be used, such as to constrain light provided by particular LEDs. Coded light illumination can be used with a focal plane array light imager receiving response light for inspecting a moving semiconductor or other target. Encoding can use orthogonal functions, such as an RGB illumination sequence, or a sequence of combinations of spectrally contiguous or non-contiguous colors.

A spectrometry device includes a switch and a converter. The switch acquires a first reception signal and a second reception signal that respectively include information relating to an optical spectrum and switches between outputting the first reception signal and outputting the second reception signal based on control by a controller. The converter converts the first reception signal or the second reception signal output from the switch into a digital signal.

A spectrometry device includes a switch and a converter. The switch acquires a first reception signal and a second reception signal that respectively include information relating to an optical spectrum and switches between outputting the first reception signal and outputting the second reception signal based on control by a controller. The converter converts the first reception signal or the second reception signal output from the switch into a digital signal.

A spectroscopic laser sensor based on hybrid III-V/IV system-on-a-chip technology. The laser sensor is configured to either (i) be used with a fiber-optic probe connected to an intravenous/intra-arterial optical catheter for direct invasive blood analyte concentration level measurement or (ii) be used to measure blood analyte concentration level non-invasively through an optical interface attached, e.g., to the skin or fingernail bed of a human. The sensor includes a III-V gain-chip, e.g., an AlGaInAsSb/GaSb based gain-chip, and a photonic integrated circuit, with laser wavelength filtering, laser wavelength tuning, laser wavelength monitoring, laser signal monitoring and signal output sections realized on a chip by combining IV-based semiconductor substrates and flip-chip AlGa1-nAsSb/GaSb based photodetectors and embedded electronics for signal processing. Embodiments of the invention may be applied for real-time monitoring of critical blood analyte concentration levels such as lactates, urea, glucose, ammonia, albumin, etc.

Building blocks are provided for on-chip chemical sensors and other highly-compact photonic integrated circuits combining interband or quantum cascade lasers and detectors with passive waveguides and other components integrated on a III-V or silicon. A MWIR or LWIR laser source is evanescently coupled into a passive extended or resonant-cavity waveguide that provides evanescent coupling to a sample gas (or liquid) for spectroscopic chemical sensing. In the case of an ICL, the uppermost layer of this passive waveguide has a relatively high index of refraction that enables it to form the core of the waveguide, while the ambient air, consisting of the sample gas, functions as the top cladding layer. A fraction of the propagating light beam is absorbed by the sample gas if it contains a chemical species having a fingerprint absorption feature within the spectral linewidth of the laser emission.

In an illustrative configuration, a method for monitoring air quality is disclosed. The method includes accepting analyte gas into a cell and reflecting light rays into the analyte gas repeatedly across the cell into at least one sensor. The light scattered by particulate matter in the analyte gas and amount of spectra-absorption due to presence of a gaseous chemical is then measured. Based on the determined amount of spectra-absorption and the measured scattered light the gaseous chemical is then measured.

Methods and systems are provided for separating polarized UV light. In one example, a method may include passing polarized source light through a first prism, the polarized source light including desired light and undesired light, separating the desired light from the fundamental light, and passing the separated desired light through a second prism. The separated desired light which is passed through the second prism may then be further passed through a spatial filter.

Embodiments of the disclosure are drawn to apparatuses and methods for anomalous gas concentration detection. A spectroscopic system, such as a wavelength modulated spectroscopy (WMS) system may measure gas concentrations in a target area. However, noise, such as speckle noise, may interfere with measuring relatively low concentrations of gas, and may lead to false positives. A noise model, which includes a contribution from a speckle noise model, may be used to process data from the spectroscopic system. An adaptive threshold may be applied based on an expected amount of noise. A speckle filter may remove measurements which are outliers based on a measurement of their noise. Plume detection may be used to determine a presence of gas plumes. Each of these processing steps may be associated with a confidence, which may be used to determine an overall confidence in the processed measurements/gas plumes.

Techniques are disclosed for a chemical sensor architecture based on a fabric-based spectrometer. An example apparatus implementing the techniques includes a portable spectrometer device including a first fabric layer and a second fabric layer coupled to the first fabric layer to form a pouch. The second fabric layer includes a fiber fabric spectrometer substrate comprising a fiber material including one or more electronic devices, wherein the pouch is configured to receive a colorimetric substrate and the fiber fabric spectrometer substrate is configured to measure reflectance of a colorimetric substrate disposed in the pouch.