A duplex wideband grating includes a first diffraction element and a second diffraction element. The first diffraction element and the second diffraction element may reside in a single volume or in two separate volumes. The first diffraction element may include a first set of Bragg planes, and the second diffraction element may include a second set of Bragg planes. The first diffraction element may be designed to have a peak diffraction efficiency at a first wavelength, and the second diffraction element may be designed to have a peak diffraction efficiency at a second wavelength different from the first wavelength. The first diffraction element and the second diffraction element may be designed to achieve a same angle of dispersion between wavelengths. The duplex wideband grating may have a broader bandwidth with higher average diffraction efficiency across the broader bandwidth than either the first diffraction element or the second diffraction element.

Apparatuses, systems, and methods for Raman spectroscopy are described. In certain implementations, a spectrometer is provided. The spectrometer may include a plurality of optical elements, comprising an entrance aperture, a collimating element, a volume phase holographic grating, a focusing element, and a detector array. The plurality of optical elements are configured to transfer the light beam from the entrance aperture to the detector array with a high transfer efficiency over a preselected spectral band.

A method includes receiving collimated light from an optical imaging system and dividing the received light into multiple bands of wavelength. Each band is refocused onto a corresponding diffraction grating having an amplitude function matched to a point spread function (PSF) of the optical imaging system. The light that is not filtered out by the diffraction grating is transmitted onto a corresponding pixel array. An image is reconstructed from data provided by the pixel arrays for each band. The intensity of light scattered by each diffraction grating may be detected, with the image being reconstructed as a function of an average value of detected intensity of scattered light used to scale the known zero-order mode profile, which is added to the image on the pixel array.

An optical device and a spectral detection apparatus are provided. The optical device includes an optical waveguide, including: a polychromatic light channel configured to transport a polychromatic light beam, and provided with a light incident surface for receiving the incident polychromatic light beam at an input end of the polychromatic light channel; a chromatic dispersion device arranged downstream from the polychromatic light channel in an optical path and configured to separate the polychromatic light beam from the polychromatic light channel into a plurality of monochromatic light beams; and a plurality of monochromatic light channels arranged downstream from the chromatic dispersion device in the optical path and configured to respectively conduct the plurality of monochromatic light beams with different colors from the chromatic dispersion device. Monochromatic light output surfaces are respectively provided at output ends of the plurality of monochromatic light channels and configured to output the monochromatic light beams.

The disclosure relates to an optical spectrometer (1) for spectrally resolved two-dimensional imaging of an object (0), comprising a dispersing device (2) arranged to disperse radiation from object (0), a multi-lens array arrangement (3) arranged to receive the dispersed radiation from the dispersing device (2), a two-dimensional detector (4) arranged to receive the dispersed radiation as directed by the multi-lens array arrangement (3), wherein the optical spectrometer (1) further comprises a collimating arrangement (5) for collimating the radiation from object (0) before the radiation reaches the dispersing device (2), the collimating arrangement (5) comprising a diffusing plate (6) for diffusing the radiation and an optical micro-channel component (7) arranged to receive the diffused radiation comprising a plurality of parallel and linear optical micro-channels directed towards the dispersing device (2). The disclosure further relates to a method for spectrally resolved two-dimensional imaging of an object (0).

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.

An optical system operating in the near or short-wave infrared wavelength range identifies an object based on water absorption. The system comprises a light source with modulated light emitting diodes operating at wavelengths near 1090 and 1440 nanometers, corresponding to lower and higher water absorption. The system further comprises one or more wavelength selective filters and a housing that is further coupled to an electrical circuit and a processor. The detection system comprises photodetectors that are synchronized to the light source, and the detection system receives at least a portion of light reflected from the object. The system is configured to identify the object by comparing the reflected light at the first and second wavelength to generate an output value, and then comparing the output value to a threshold. The optical system may be further coupled to a wearable device or a remote sensing system with a time-of-flight sensor.

An apparatus includes a substrate transmissive of electromagnetic energy of at least a plurality of wavelengths, having a first end, a second end, a first major face, a second major face, at least one edge, a length, a width, and a thickness, at least a first nanostructure that selectively extracts electromagnetic energy of a first set of wavelengths from the substrate; and an input optic oriented and positioned to provide electromagnetic energy into the substrate via at least one of the first or the second major face of the substrate. Nanostructures can take the form of photonic crystal arrays, a plasmonic structure arrays, or holographic diffraction gratings. The apparatus may be part of a spectrometer.

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.

An active remote sensing system is provided with an array of laser diodes that generate light directed to an object having one or more optical wavelengths that include at least one near-infrared wavelength between 600 nanometers and 1000 nanometers. One of the laser diodes pulses at a modulation frequency between 10 Megahertz and 1 Gigahertz and has a phase associated with the modulation frequency. A detection system includes a photo-detector, a lens, a spectral filter at an input to the photo-detector, and a processor that processes digitized signals received from the photo-detector to generate an output signal. The detection system uses a lock-in technique that synchronizes pulsing the one laser diode. The active remote sensing system is configured to be mounted on a vehicle or an airborne platform to provide distance information based on a time-of-flight measurement.