Differential optical absorption spectroscopy measurement system based on off-axis paraboloid mirror

Abstract

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.

Description

technical field [0001] The invention belongs to the field of optical measurement, in particular to a differential absorption spectrum system based on an off-axis parabolic mirror for transmitting and receiving, which is applied to monitor atmospheric trace pollution gases. Background technique [0002] Spectral analysis technology can use different molecules to perform qualitative and quantitative measurements of the characteristic absorption of light radiation in the wavelength band. Information such as the composition and concentration of a substance can be obtained by analyzing its absorption spectrum. This technology is widely used in the fields of atmospheric toxic and harmful gas monitoring and water body monitoring. DOAS technology is a non-contact and open optical path measurement method for trace gas detection. Its basic principle is to use the narrow-band absorption characteristics of different gas molecules to light radiation to identify gas components, and to in...

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