A Differential Optical Absorption Spectroscopy Measurement System Using Polarization Spectroscopy

Abstract

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.

Description

technical field [0001] The invention relates to a differential optical absorption spectrum air quality measurement system with an integrated optical path for transmitting and receiving, in particular to a high-sensitivity monitoring system for detecting trace amounts of toxic and harmful gases in the air. technical background [0002] With the rapid development of my country's economy and the acceleration of industrialization and urbanization, environmental pollution problems have also followed, especially in recent years, regional air pollution problems such as photochemical pollution and haze fine particle pollution have seriously exceeded the standard. , the situation of air pollution is becoming increasingly prominent. Environmental monitoring is an important part of environmental protection, and the improvement of environmental monitoring technology plays an important role and significance in promoting environmental protection and sustainable development. Differential O...

AI Technical Summary

Problems solved by technology

However, there are the following problems in the actual measurement. Usually, the receiving part of the common end of the transceiver fiber is designed at the focal position of the main mirror of the telescope, while the transmitting part is at the defocused position. However, this will cause part of the light radiation to irradiate the main mirror of the telescope. The transmission in the atmosphere is directly reflected back to the receiving end, resulting in large stray light inside the telescope

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