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.

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.

This gas analysis device comprises: a laser light source which irradiates a gas to be measured with laser light; a laser control means which controls the laser light source so that the wavelength of the laser light is changed in each prescribed wavelength band; a light detection means which photoelectrically converts the laser light that have passed through the gas to be measured and outputs an electrical signal; and an interpretation means which analyzes, on the basis of the electrical signal, an absorption wavelength of the gas to be measured. In the gas analysis device, the laser control means controls the laser light source so that the intensity of the laser light changes into a shape (for example, a rectangular shape or a trapezoidal shape) having at least a substantially constant flat part in a prescribed time period, and the wavelength of the laser light changes in the time period.

A light emitting and receiving apparatus includes a controller and a calculator. The controller acquires a first detection current from a light-receiving element when supplying a first drive current to a light-emitting element and acquires a second detection current from the light-receiving element when supplying a second drive current to the light-emitting element. The calculator generates a signal indicating deterioration of the light-emitting element when a reference value and an aging value satisfy a deterioration judgment condition, the aging value being a ratio between the first detection current and the second detection current. The detection accuracy of the light emitting and receiving apparatus is thereby improved.

A sensor device and a method of analyzing a component in a fluid are described. The sensor device comprises a planar substrate defining a substrate plane, an electromagnetic waveguide forming a waveguide resonator and extending in a length direction in a waveguide resonator plane parallel to the substrate plane, wherein the electromagnetic waveguide is supported on the substrate by a support structure, wherein the electromagnetic waveguide has a width in the waveguide resonator plane in a direction perpendicular to the length direction, and a height out of the waveguide plane in a direction perpendicular to the length direction.

A portable optical spectroscopy device is disclosed for analyzing gas samples and/or for measurement of species concentration, number density, or column density. The device includes a measuring chamber with the gas sample to be analyzed, a light source with at least one laser diode for emitting a laser beam along a light path running through the measuring chamber at least in certain regions, means for modulating the wavelength of the light beam emitted by the light source, and an optical detector device having a first optical detector and at least one second optical detector. At least a part of the light emitted by the laser diode is detected after the light has passed through the measuring chamber m-times, and at least a part of the light emitted by the laser diode is detected with the at least one second optical detector after the light has passed through the measuring chamber n-times, where n>m applies.

An apparatus adapted to perform spectrometric measurements, said apparatus comprising a tunable laser light source adapted to generate a laser light with an excitation wavelength supplied to an optical sensor which produces a sample specific response light signal; an optical reference filter adapted to measure laser light with the excitation wavelength fed back as a reference signal to provide wavelength calibration of the tunable laser light source; at least one optical measurement filter adapted to measure the sample specific response light signal produced by the optical sensor, wherein the optical reference filter and the at least one optical measurement filter are thermally coupled to maintain a constant wavelength relationship between the filter characteristics of the optical filters.

A system for measuring a target gas via laser absorption spectroscopy in an open-air configuration, comprising a mid-infrared distributed feedback interband cascade laser (mid-IR DFB-ICL) having a wavelength selected to correspond with a spectral absorption line of the target gas and first electronic circuitry to control the laser temperature, current and modulation frequency. The mid-IR DFB-ICL is mounted to a heat sink. The system includes an optical component that projects a beam of the mid-IR DFB-ICL onto a distal backscattering directionally-reflective target and an optical receiver assembly that receives a fraction of the laser light that is backscattered from the directionally-reflective target and focuses the collected light onto an uncooled photodetector having a spectral bandwidth and optical configuration selected to optimize signal-to-noise response to received laser light. The optical receiver assembly comprises a primary mirror for receiving laser light backscattered from the directionally-reflective target and focusing the collected light onto the uncooled photodetector.

A gas analyzer that easily facilitates alignment is provided. The gas analyzer is a gas analyzer for measuring a predetermined component in a measurement gas by irradiating light on the measurement gas from a light emitting element and receiving light that passes through the measurement gas. The gas analyzer includes a base member configured to be adjustable in position along at least one axis that is not parallel to the optical axis of the light emitting element, and a holding member configured to hold the light emitting element and to be held to the base member in an angularly adjustable manner around at least one axis that is not parallel to the optical axis.

A gas analysis system, includes: a light-emitting element that emits a laser light modulated by a predetermined modulation frequency; and a light-receiving element that: receives the laser light that has passed through a measurement target gas; and upon receiving the laser light, outputs a received signal having an N-frequency that is n times the predetermined modulation frequency, wherein n is an integer no less than 2; and a signal processing device that: calculates a third component by removing, from a first component having the N-frequency, a second component, wherein the second component is a component of optical interference noise arising on an optical path of the laser light from the light-emitting element to the light-receiving element and has the same frequency as the first component; and calculates, based on a magnitude of the third component, a concentration of the measurement target gas.