A method of measuring a concentration of NO.sub.2 in a gaseous mixture using a multimode laser beam that covers a tunable spectral range with a width of no more than 5 nm, wherein the multimode laser beam provides a high resolution transmittance spectrum at an absorption cross section of NO.sub.2 molecules, and a system for measuring the concentration of NO.sub.2 in the gaseous mixture. Various combinations of embodiments of the system and the method are provided.

An in-situ sensor system that is configured to be placed inside of an oxygen mask for a pilot. The sensor system is readily placed in a position over the exhalation valve such that it can capture data from the exhaled air of the pilot. The sensor system has an optical sensor element that can capture data real time and feed the data to a control module that can subsequently be use to generate output data for the pilot and/or ground elements.

Disclosed is a spectroscopic device, system, and method for measuring the concentration of one or more molecular species of interest in a gas, liquid or solid sample, where the device may be portable, may be commercially manufactured, and/or may be adapted to existing systems and/or integrated with new systems to provide optical gas sensing for such systems. The disclosed devices, systems, and methods can be particularly useful in monitoring the purity of, e.g., a certain gas species, including determining whether a gas mixture contains certain gas species above a set concentration limit.

A gas analysis system and method using a spectrometer, such as a Fourier transform infrared spectrometer, utilizes a reactor, such as a catalytic reactor, for providing interference spectra. The gas is pressurized and chilled to remove water prior to the spectrometer.

Multi-pass cavities for cavity ring-down spectroscopy. The multi-pass cavity includes, in one example, a body, a pair of flat mirrors, a light input coupler, a first turning mirror, a second turning mirror, and a light output coupler. The pair of flat mirrors are positioned parallel to each other within a gas channel of the body. The light input coupler is configured to direct a light beam into the gas channel along a first transmission axis. The first turning mirror is configured to reflect the light beam from the first transmission axis toward the resonance cavity. The light output coupler is configured to direct a first portion of the light beam out of the gas channel and reflect a second portion of the light beam along a second transmission axis. The second turning mirror is configured to reflect the light beam from the second transmission axis to the resonance cavity.

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.

A measurement system is provided with an array of laser diodes to generate light having one or more optical wavelengths. A detection system is provided with at least one photo-detector, a lens and a spectral filter at an input to the at least one photo-detector. The measurement system is further configured to transmit at least a portion of the output signal, indicative of an output status, to a cloud service over a transmission link. The cloud service is configured to receive the output status, to generate processed data based on the received output status, and to store the processed data, and wherein the cloud service is capable of storing a history of at least a portion of the received output status over a specified period of time.

An apparatus or method for measurement of multiple gas concentrations. The apparatus comprises a multi-wavelength laser module, and a multi-layered/multi-band detector.

A method for assessing spectroscopic sensor accuracy, includes building an a priori simulation of generalized etalon drift. A spectroscopic sensor is tested to determine use parameters. A specific drift model is generated by applying the determined use parameters to the built a priori simulation of generalized etalon drift. The specific drift model is analyzed to determine whether the spectroscopic sensor is satisfactory.

A method of measuring a concentration of NO.sub.2 in a gaseous mixture using a multimode laser beam that covers a tunable spectral range with a width of no more than 5 nm, wherein the multimode laser beam provides a high resolution transmittance spectrum at an absorption cross section of NO.sub.2 molecules, and a system for measuring the concentration of NO.sub.2 in the gaseous mixture. Various combinations of embodiments of the system and the method are provided.