Laser radar frequency locking device and method for gas detection

Abstract

The invention discloses a laser radar frequency locking device and method for gas detection. A first laser signal with the same wavelength as a target absorption line of to-be-detected gas is output to a light intensity modulator through a laser light source, a signal generation device outputs a first modulation signal to the light intensity modulator so as to generate two symmetrical sideband signals, and the signals output by the light intensity modulator pass through a gas absorption cell and then are detected by a laser frequency detection device; and the signal generation device outputs abias voltage signal to the light intensity modulator, so that the signal intensity corresponding to lambda 1 and lambda 2 in the signals output by the laser frequency detection device is the same. According to the invention, the offset of the laser frequency can be accurately detected through the modulation signal of the light intensity modulator, and the laser frequency is accurately locked through the bias voltage signal of the light intensity modulator. The laser radar frequency locking device is ingenious in conception, compact in structure, convenient to operate, low in cost, flexible inapplication and capable of being applied to accurate locking of laser frequency in various gas detection.

Description

technical field [0001] The invention relates to the field of laser radar atmospheric remote sensing, in particular to a laser radar frequency locking device and method for gas detection. Background technique [0002] Gas detection is of great significance to the study of air pollution and atmospheric composition. Differential absorption lidar can effectively measure atmospheric gas composition. Differential absorption lidar emits two laser beams with similar wavelengths into the atmosphere during gas detection, one of which wavelength is on the absorption line of the gas to be measured, which is strongly absorbed by the gas to be measured, called the on-line wavelength (on wavelength); The wavelength is on or outside the absorption line of the gas to be measured, and the gas to be measured absorbs little or no absorption on it, which is called the off-line wavelength (off wavelength). Since the two laser beams have similar wavelengths, the extinction of other gas molecules ...

AI Technical Summary

Problems solved by technology

Since the online wavelength and the offline wavelength are very close, if the online wavelength and frequency drift away from the gas absorption line, the difference between the measured online signal and the offline signal will be significantly reduced, and even no effective signal can be measured, which is the key to the gas detection zone. big error

Images