34 results about "Differential optical absorption spectroscopy" patented technology

The invention discloses a reconstruction method for atmosphere trace gas spatial distribution by differential optical absorption spectroscopy tomoscan, which is characterized in that two differential absorption scan optics remote measurement assemblies arranged at two sides of air mass to be measured according to an initial observation angle are performed with simultaneous and timing intersect scanning, an intersect sector light beam geometric optical path is constructed, measurement is carried out according to measurement interval which is determined by sampling rate and ray quantity together, a processor can accurately acquire the characteristic differential absorption spectroscopy of atmosphere trace gas at ultraviolet and visible wave band according to measured spectroscopy data, line integral concentration of the trace gas along the whole optical path is parsed from total atmosphere delustring information; under a sector light beam ray geometric structure, accurate inverting line integral concentration is taken as projection vector, an atmosphere trace quantity component spatial distribution reconstruction algorithm is employed, and a visual two dimensional or three dimensional atmosphere trace gas spatial distribution graph is finally formed. According to the invention, the visual atmosphere trace gas spatial distribution integral information graph can continuously and accurately provide the multi-component atmosphere environment pollution gas at real-time online.

The invention discloses an introduction optical system of a differential absorption spectrometer, which is characterized in that a telescope is arranged, and an optical filter and a lens group are sequentially arranged on the follow-up optical path of the telescope, and the light emitted from the lens group is imaged on the incident slit of the differential absorption spectrometer above; the filter is a 490nm-700nm visible light filter or a 287nm-490nm ultraviolet filter; the lens group is composed of three positive lenses and two negative lenses intersecting, The incident light in the direction of the ground enters the telescope and is guided into the lens group through the filter sheet. The invention adopts the transmission method to separately receive and image the ultraviolet waveband and the visible light waveband, thereby effectively reducing the aberration and improving the measurement accuracy.

The invention provides a differential absorption spectrum air quality inspecting system, which comprises a photo source, a photo source launching device, a photo source receiving device, a spectroscope, photovoltaic conversion equipment and a data processing system. The photo source launching device and the photo source receiving device are separately positioned on the two sides of the photo source, a light path which goes through the gas to be inspected is formed of the light sent out by the photo source through the photo source launching device and the photo source receiving device, and thelight signal produced is imported into the spectroscope through optical fiber, and the light signal is then transformed into electrical signal through the photo electricity commutating equipment; Finally, the data processing system adopts the signal analysis method of the Fourier transformation to process the spectrum, and the absorbance curve line of the gas inspected is obtained; and the density of the gas inspected can be obtained according to the intensity of the absorbance curve line and the Lambert-beer law.

The invention provides an optical fiber transceiver integrated air differential optical absorption spectroscopy (DOAS) measuring system, which solves the problems of low spectrum utilization ratio and difficulty in instrument adjustment and optical path centering of the existing typical DOAS system. The measuring system comprises a point light source, a telescope, a spectrograph and an optical fiber bundle with a transceiver integrated structure, wherein, the optical fiber bundle with the transceiver integrated structure is composed of transmitting optical fiber and receiving optical fiber and provided with an optical fiber transceiver common port. The spectrum sent by the point light source is transmitted through the optical fiber transceiver common port from one end of the transmitting optical fiber, aligned through a spherical reflector in the telescope, reflected along the original direction after reaching a pyramid prism, focused through the spherical reflector and then enters the optical fiber transceiver common port, and finally transmitted through the other end of the receiving optical fiber and then led into the spectrograph for spectrum detection. Compared with the typical DOAS system, the measuring system reduces two plane reflectors, avoids a light beam being sheltered by the plane reflector during the transmission process, improves the spectrum utilization ratio and simplifies the instrument adjusting and centering process.

The invention belongs to the technical field of optical measurement and specifically relates to an LED light source-based differential optical absorption spectroscopy system for measuring concentration of glyoxal in the atmosphere. The system of the invention is composed of an LED light, a plane mirror, a main concave mirror, an optical corner reflector, a secondary mirror, a fiber, a spectrometerand a computer, etc. A virtual image generated by the LED light in the plane mirror is positioned near the focus of the main concave mirror; after collimation by the main concave mirror, light beamsenter the atmosphere and reach the optical corner reflector after transmitted for some distance; the light beams are reflected back to the main concave mirror along the original path and are gatheredto the fiber after focusing by the secondary mirror; after light splitting by a spectrometer and photoelectric conversion, absorption spectrum information is obtained; by the least square method for spectral interpretation, the calibrated NO2 standard absorption spectrum is used as a fitting item for inversion of glyoxal to reduce the interference of NO2 with analysis of glyoxal, thereby achievingaccurate measurement of concentration of glyoxal in the atmosphere.

The invention provides a differential optical absorption spectroscopy (DOAS) measurement system based on an off-axis paraboloid mirror. The DOAS measurement system comprises an off-axis paraboloid mirror (center punched) telescope, a light source (LED) device, a light source coupling lens, a light source collimating lens, a corner reflector, an optical fiber and a spectrograph detector. Light emitted from the light source device is coupled by a lens to enter the optical fiber, enters atmosphere through a small hole in the center of the off-axis paraboloid mirror after being collimated by the collimating mirror, returns the off-axis paraboloid mirror telescope after being reflected by the corner reflector through a certain distance of transmission, enters a receiving optical fiber through off-axis convergence and coupling and transmitted to the spectrograph, and is received by the detector after being split by the spectrograph, thereby being subjected to post-stage spectrum analysis. Compared with a conventional DOAS system, the DOAS measurement system provided by the invention has the advantages that the receiving efficiency of the telescope is increased, and the system is simplified to ensure that receiving an optical signal and emitting an optical signal are separated to facilitate the system adjustment through designing a simple structure inside the telescope.

The invention discloses a device and a method for detecting the concentration of harmful gases in a sample gas. The method comprises the following steps of: collimating ultraviolet light beams emitted by an ultraviolet light source by using a first lens group, and removing second large spectral beams from the ultraviolet light beams by using a narrow band pass filter; transmitting the ultraviolet light beams of which the second large spectral beams are filtered off to a flowing cell through an input optical fiber, and after the ultraviolet light beams are absorbed by the sample gas in the flowing cell, focusing the ultraviolet light beams onto an output optical fiber through a second lens group; transmitting the ultraviolet light beams which are absorbed to an incident slit of a spectrograph through the output optical fiber, and splitting by using a monochromator to obtain a light spectrum arranged according to wavelengths; and detecting the light spectrum by using a photoelectric detector, converting optical signals corresponding to various wavelengths into electric signals, performing a differential optical absorption spectroscopy (DOAS) algorithm-based fast Fourier transform on the electric signals, and calculating the concentration of SO2 and NO in the sample gas.

The invention discloses a DOAS measurement system by means of polarizing beam splitting. The DOAS measurement system comprises a lambda / 4 wave wafer, a polarizing beam splitting piece, a parabolic mirror primary mirror, a corner mirror, an optical fiber, a power source device and a spectrograph detector. By means of the characteristics of the polarizing beam splitting piece, due to the fact that a signal carrying an absorbing spectrum passes through the lambda / 4 wave wafer for two times, the polarizing state will change, and the signal will be reflected to the receiving optical fiber by the polarizing beam splitting piece; due to the fact that a telescope stray light signal which does not carry the absorbing spectrum and is not in atmospheric transmission does not pass through the lambda / 4 wave wafer, the polarizing state does not change, and the signal passes through the polarizing beam splitting piece and will not be reflected to the receiving optical fiber by the polarizing beam splitting piece. Compared with an existing light-path receiving and transmitting integrated DOAS measurement system, the DOAS measurement system can reduce the proportion of stray light inside a telescope and scattered light in the atmospheric background in the measurement signals, also improve the signal to noise ratio of DOAS measurement on the premise that the lighting effect is ensured, and improve the detection precision of the DOAS.

The present invention relates to a high sensitivity optical system of a differential optical absorption spectroscopy (DOAS) analyzer for gas concentration detection. According to the system, two optical axes of a collimating lens set and a condenser lens set intersect on a side of a large lens to form the optical axis intersection point, wherein the collimating lens set is arranged perpendicular to the condenser lens set; optical axes on both sides of the collimating lens set are respectively provided with a light source and a transmitted light reflector; optical axes of both sides of the condenser lens set are respectively provided with an optical fiber spectrometer and a reference light reflector; a spectroscope plated with a reflecting film is positioned on an angular bisector of a right angle, wherein the optical axes of the two adjacent sides of the collimating lens set and the condenser lens set intersect to form the right angle; the spectroscope is concurrently and obliquely arranged on the optical path comprising the half outgoing beam of the collimating lens set and the half incoming beam of the condenser lens set in the angle of 45 DEG, and the other half outgoing beam of the collimating lens set and the other half incoming beam of the condenser lens are provided with moveable baffles, wherein the positions of the movable baffles are switchable; the half of the beam emitted by the light source enters the reference light path, and the other half of the beam enters the measurement light path. According to the present invention, under the same light source radiationconditions, the light energy passing through the optical system of the present invention is strong, the signal-to-noise ratio is high, and the measurement precision is improved.