Laser absorption spectroscopy data processing method based on co-frequency and dual-wavelength and its application

In the detection process of atmospheric laser absorption spectroscopy in open space, the transmitted beam is inevitably affected by atmospheric turbulence, resulting in superimposed fluctuation noise in the received optical signal. First, the correction method of atmospheric turbulence is theoretically analyzed. In order to reduce the error influence factors and the error transfer coefficient, a new method of spectral data processing based on cofrequency and dual-wave has been proposed. By modifying scintillation noise and background noise, the influence of atmospheric turbulence noise in open space is reduced. An atmospheric detection system in open space based on co-frequency and dual-wave has been established. The experimental results show that the maximum fluctuation of the spectral signal processed by the method of spectrum data processing based on the co-frequency and dual-wave is reduced from 12.854% to 4.635%, and the single-intensity absorbance is fitted by Voigt with its correlation coefficient of 0.9525. The mean of the standard deviation of the algorithm is 0.1370, while the mean value of the standard deviation of the existing algorithm in a short time is 0.6928. And, through the comparative experiment, the standard deviation of the existing data processing techniques of two-wavelength differential absorption is 0.2974, while the standard deviation of the method of spectrum data processing based on the cofrequency and dual-wave is 0.1038. It can be concluded that the co-frequency and dual-wave method can effectively reduce the influence of atmospheric turbulence noise and laser flashing to improve the stability of concentration measurement, which has practical engineering value. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.