激光在不同类型气溶胶中传输特性研究

摘要

激光在大气中的传输衰减特性是激光工程应用中需要考虑的一个重要问题.本文针对常用的1.06 μm和10.6μm激光,基于Mie散射理论计算了气溶胶粒子的单次散射参量;对于激光在气溶胶中多次散射传输衰减,建立了蒙特卡罗模拟计算模型,利用Matlab语言编制了相应的计算程序,计算分析了两种波长的激光分别在沙尘性、水溶性、海洋性和煤烟性四种不同类型气溶胶中透过率与传播距离、能见度的关系,并将蒙特卡罗方法和单次散射的计算结果进行了比较.结果表明,当能见度较低、气溶胶粒子反照率较高时,单次散射计算存在很大的误差,用蒙特卡罗方法更能揭示多重散射现象;煤烟性气溶胶对1.06 μm激光的传输衰减影响最大,沙尘性气溶胶对10.6 μm激光的传输衰减影响最大.%The characteristics of laser transmission in atmosphere are an important issue that must be considered for applications in laser engineering. For 1.06 μm and 10.6 μm laser, the single scattering parameters of aerosols are calculated based on the Mie scattering theory. For the transmission attenuation of the laser in aerosol, the Monte Carlo simulation model is established. For dust-like, water-soluble, oceanic and soot four types of aerosols, the relations of transmittance to visibility and propagation distance are computed and analyzed using the program written in MATLAB language respectively. The results show that single scattering calculation has a larger error when the visibility is low, and albedo is high. Using the Monte Carlo method to calculate the attenuation of the laser transmission in aerosol can reveal multiple scattering phenomenon. For the 1.06 μm laser, the attenuation capacity of soot aerosol is strongest, and for the 10.6 μm laser, the attenuation capacity of dust-like aerosol is strongest.