A detection method and detection system for a trace gas, the detection method comprising: providing a resonant cavity, a gas to be measured being filled inside of a cavity body of the resonant cavity; providing detection light rays having different frequencies, the detection light rays being incident to the inside of the resonant cavity from one end of the resonant cavity in the extending direction and exiting from the other end of the resonant cavity in the extending direction so as to obtain detection light rays carrying information of a trace gas to be measured, and the cavity body of the resonant cavity having a degree of freedom of expansion and retraction in the extending direction so that the longitudinal mode frequency of the resonant cavity matches the frequencies of the incident detection light rays; and according to the detection light rays that have different frequencies and that carry information of said trace gas, acquiring the molecular saturation absorption spectrum of said trace gas, and calculating the concentration of said trace gas. The detection system comprises: a laser generating device, the resonant cavity, a photoelectric detection device, a feedback control device and a scanning control device. At room temperature, detection light rays provided by a conventional laser are used to detect the concentration of a trace gas.

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.

The present invention relates to a novel analysis device and method for obtaining the concentration of dissolved inorganic carbon (DIC) and isotopic carbon and oxygen concentration thereof, continuously from a liquid sample.

A cavity enhanced absorption spectroscopy (CEAS) system is provided that utilizes collimators the incorporate gradient index (GRIN) lenses in lieu of conventional spherical or aspheric refractive lenses. The use of smaller diameter GRIN lenses facilitates a reduced initial beam size entering the sample cavity, which reduces self-interference noise and increases a signal to noise ratio of the measurements. Further, a reduced size and mass of the GRIN lens can reduce a size of the mounting hardware utilized to mount the optical components, which enables more laser beams to be coupled to a single gas cell compared to a similar gas cell integrated with conventional refractive collimators. A larger number of lasers enables more gas peaks to be measured substantially simultaneously using the CEAS system.

An apparatus and a method for quantitative detection of gases are provided. The apparatus for quantitative detection of gases includes: a cavity ring-down spectroscopy device configured to quantitatively detect any characteristic gas in gases to be detected; a sample processing device disposed in a downstream of the cavity ring-down spectroscopy device and connected to the cavity ring-down spectroscopy device; and a mass spectrometry device disposed in a downstream of the sample processing device and configured to detect all the gases to be detected. Quantitative analysis of any variety of gases may be achieved without using standard gas in the technical solution proposed by the present application. Since no standard gas is required, the technology has significantly increased flexibility, and can be used for routine laboratory testing, for online analysis at industrial sites, as well as detection and analysis in environmental protection, national defense, aviation, aerospace, military and other fields.

Systems, devices, and methods including one or more optical cavities; one or more light sources configured to emit a specified wavelength or band of wavelengths of light; and one or more photovoltaic detectors configured to receive the emitted light that has traveled over one or more path lengths, where the one or more photovoltaic detectors are configured to detect at least one of: a first trace gas species and a second trace gas species.

Methods and systems for analyzing a sample and generating a predictive model using cavity ring-down spectroscopy are disclosed. At least part of a sample is loaded in a ring-down cavity. For each of a set of wavelengths, a laser beam is generated and directed into the ring-down cavity. The laser beam entering the ring-down cavity is extinguished. Light intensity decay data for light exiting the ring-down cavity is registered via a light intensity sensor system. A probability is determined from the light intensity decay data for the set of wavelengths that a subject from which the sample was received has a physiological condition or a degree of the physiological condition at least indirectly using a dataset of light intensity decay data for previously analyzed samples for which the presence or the absence of the physiological condition or the degree of the physiological condition have been identified.

An interferometric fluid sensing system is provided. The system comprises: a laser; a plurality of first fibre portions arranged to receive laser light from the laser, wherein each of the first fibre portions comprises a void and an opening to allow fluid from the environment around the corresponding first fibre portion to enter the void, wherein the first fibre portions are configured such that the laser light received by each first fibre portion passes through the corresponding void; a second fibre portion configured to provide a reference arm for the interferometric fluid sensing system; and a detector arranged to receive light from the first and second fibre portions, wherein the system is configured such that the laser light that passes through the void of each first fibre portion is caused to interfere with the light passing through the second fibre portion at or before reaching the detector, wherein each of the first fibre portions is arranged such that that light passing through the void of each first fibre portion travels from the laser to the detector over a different path length from the light passing through the voids of the other first fibre portions, wherein the system is configured such that the wavelength of light provided by the laser varies with time according to a modulated function, the modulated function comprising a first function, which varies through a range of wavelengths, modulated by a second, cyclical carrier function. An interferometric fluid detection method is also provided.

Methods and systems for analyzing a sample and generating a predictive model using cavity ring-down spectroscopy are disclosed. At least part of a sample is loaded in a ring-down cavity. For each of a set of wavelengths, a laser beam is generated and directed into the ring-down cavity. The laser beam entering the ring-down cavity is extinguished. Light intensity decay data for light exiting the ring-down cavity is registered via a light intensity sensor system. A probability is determined from the light intensity decay data for the set of wavelengths that a subject from which the sample was received has a physiological condition or a degree of the physiological condition at least indirectly using a dataset of light intensity decay data for previously analyzed samples for which the presence or the absence of the physiological condition or the degree of the physiological condition have been identified.

A laser gas analyzer includes a light emitting unit including a laser element configured to emit laser light having a target wavelength band including a wavelength of an absorption line spectrum of the target gas, and a modulated light generation unit configured to supply a drive current to the laser element so that the laser element sweeps and modulates the laser light to have the target wavelength band, and a light receiving unit including a light receiving element configured to receive the laser light passing through the target space and output a detection signal, and a light reception signal processing unit configured to analyze the target gas according to the detection signal from the light receiving element. The light emitting unit and the light receiving unit communicate with each other using the laser light.