湍流对激光吸收光谱信号的影响及改善方法研究

Effect of turbulence on laser absorption signal and its improvement method

为了解决可调谐激光二极管吸收光谱气体传感器在开放光路气体测量中,激光吸收光谱信号受到大气湍流的影响,使光谱信号幅度随大气湍流的波动而改变造成获取的气体吸收光谱信号形状发生畸变问题,改善湍流对激光吸收光谱信号的影响,提高信号检测灵敏度,采用改变激光波长扫描频率的办法进行了理论分析和实验验证,当激光波长扫描频率为2kHz时,吸收光谱相邻周期间的信号均方误差小于0.1。结果表明,该方法可以有效地改善激光吸收光谱信号受大气湍流的影响。

When tunable diode laser absorption spectroscopy gas sensor is used in open optical path gas measurement, the laser absorption signal can be influenced by atmospheric turbulence. The amplitude of absorption signal varies with the fluctuation of atmospheric turbulence so that the obtained gas absorption spectrum signal is deformed and the measurement accuracy is affected. In order to improve laser absorption spectrum signal quality impacted by atmospheric turbulence and measurement sensitivity, a method, changing the scan frequency of laser wavelength, was put forward. The variance of average signal between adjacent periods of absorption spectrum was less than 0. 1 when the scan frequency of laser wavelength was 2kHz. This method effectively improved the laser absorption spectrum signal quality impacted by atmospheric turbulence.