Laser detection system and method for harmful gas concentration in open space atmosphere

Abstract

The invention discloses a laser detection system and method for concentration of harmful gas in an atmosphere of an open space. The laser detection system comprises a same-frequency dual-wave laser signal generation unit, a signal acquisition and processing unit, a display unit, a detection optical path and a reference optical path. By virtue of the steps of correcting the movement of center wavelength of a distribution feedback-type semiconductor laser, correcting flash noise, fitting complete non-absorptive spectral signal, normalizing, performing Voigt linear fitting, calculating the concentration, performing the inversion, and the like, the problems such as atmospheric extinction, laser flashing and wavelength drifting can be prevented, so that the real-time precision detection of thegas concentration can be realized.

Description

technical field [0001] The invention relates to the field of environmental optics, in particular to a system and method for suppressing atmospheric turbulence noise by means of multi-wavelength time-domain correlation technology and detecting gas concentration by using laser spectrum. Background technique [0002] In the process of atmospheric monitoring in open space, the concentration of detected gas is relatively low, but it is affected by the uncontrollable environment such as atmospheric turbulence and temperature, which makes it difficult to extract useful signals and noise. Atmospheric turbulence mainly causes the scintillation effect of the laser caused by the change of the refractive index of the atmospheric molecular group to cause the intensity fluctuation, phase fluctuation, beam expansion, beam drift and image point jitter of the beam, resulting in the deformation of the gas absorption spectrum line shape. [0003] The existing reduction of the influence of atmo...

AI Technical Summary

Problems solved by technology

However, in the actual application of the development of the instrument system, the influence of atmospheric turbulence is more complicated, which may easily cause detection errors

To reduce the influence of atmospheric turbulence through a high scanning frequency, the bandwidth of the laser control module is limited, so the high-frequency scanning method is limited in the development of the instrument system; increasing the receiving aperture reduces the loss of light intensity in a certain sense, but It does not fundamentally address the influence of atmospheric turbulence on spectral signals

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