The technology provides two or more spectrometers with substantially uniform focal lengths. A method includes adjusting a size of a first air gap associated with a first lens in order to modify a first focal length and securing a relative position of a first body and a second body of the first lens to set the first focal length at a first value for a first spectrometer. The method further includes adjusting a size of a second air gap associated with a second lens provided in a second spectrometer in order to modify a second focal length and securing a relative position of a first body and a second body of the second lens to set the second focal length at a second value for a second spectrometer. The first and second values are selected to render the first focal length substantially equal to the second focal length.

A spectrometer and a spectral detection and analysis method implemented by the spectrometer. The spectrometer includes an optical device and a detection device. The optical device includes at least one light filter, each of which including at least two light filtering units, so that the optical device can emit at least two kinds of monochromatic light. The detection device includes at least one detector, each of which comprising at least two detection units facing at least two light filtering units in the corresponding light filter in a one-to-one relationship. The monochromatic light emitted from the light filtering unit is emitted along the direction perpendicular to the direction of the light emitting surface.

A measurement system comprises a pulsed, near-infrared array of laser diodes, the laser diode array comprising Bragg reflectors, and wherein laser diode light is configured to penetrate tissue comprising skin. A detection system comprising a camera is synchronized to the laser diodes, and the camera is configured to receive some of the laser diode light reflected from the tissue. The detection system is configured to non-invasively measure blood within the skin, the detection system is configured to measure absorption of hemoglobin in the wavelength range between 700 and 1300 nanometers, and the processor is configured to compare the absorption of hemoglobin between different spatial locations of tissue and over a period of time. Physiological parameters are measured by the system. The measurement system is configured to use artificial intelligence in making decisions, and the system is further configured to use regression signal processing, multivariate data analysis, or component analysis techniques.

A measurement system comprises a pulsed laser diode array that includes one or more Bragg reflectors, and wherein the light generated by the array penetrates tissue comprising skin. At least some of the wavelengths of light are in the near infrared. The detection system is synchronized to the laser diode array and comprises an infrared camera and a first receiver comprising a plurality of detectors. The first receiver comprises one or more detector arrays and performs a time-of-flight measurement. The measurement system generates an image, the detection system non-invasively measures blood in blood vessels within or below a dermis layer within the skin based at least in part on near-infrared diffuse reflection from the skin, and the detection system measures absorption of hemoglobin between 700 and 1300 nanometers wavelength range. A processor compares the absorption of hemoglobin between different tissue spatial locations, and the measurement system processes the time-of-flight measurement.

A blood measurement system comprises an array of laser diodes, to generate light to penetrate tissue comprising skin, having one or more wavelengths, including a near-infrared wavelength, and Bragg reflector(s). At least one of the laser diodes to pulse at a pulse repetition rate between 1-100 megahertz. A detection system to measure blood in veins based at least in part on near-infrared diffuse reflection from the skin, the detection system comprising a photo-detector and a lens system coupled to the photo-detector, wherein the photo-detector is coupled to analog-to-digital converter(s) and a processor, and configured to measure absorption of hemoglobin in the near-infrared wavelength between 700-1300 nanometers, differentiate between regions in the skin with and without distinct veins, and implement pattern matching and a threshold function to correlate detected blood concentrations with a library of known concentrations to determine overlap.

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.

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.

The present invention relates to a highly portable, highly flexible standard of distance chemical detector such as can be used, for example, for standoff detection of explosives. Aspects of the invention include techniques for portability compactness and ways to diminish influence of fluorescence on Raman spectroscopy. Additional features can include a compact imaging spectrometer, a wirelessly connected smart device for user interface, and an auto-focus/range finder.

This application discloses an in-line system and method for measuring the optical performance of an HOE in motion during a roll-to-roll fabrication process.