基于分形理论的不同大气环境对激光传输特性影响的研究

Research on the Effect of Laser’s Transmission Characteristic by Various Atmosphere Environment Based on Fractal Theory

摘要: 在实验室中模拟平稳大气环境和同等浓度的水蒸气环境与烟雾环境，获取氦氖激光器在三种环境下的激光光斑图像。利用Matlab处理光斑图像得到其灰度图，并提取出光斑轮廓线。编写程序计算光斑的分形维数，得到的结果表明：平稳大气环境对激光传输特性影响较小，分形维数也较小；同等浓度的水蒸气环境和烟雾环境，水蒸气对激光的传输特性影响较大，分形维数较大，光斑直径较大，能量密度较小；可以利用激光光斑分形维数来研究不同环境对激光传输特性的影响。

Abstract: We simulate stable atmospheric environment and the same concentration of water vapor envi-ronment and smoke environment in our lab, and then we get the laser spot of our helium-neon laser in these three different environments with CCD sensor. Dealing with these images to get grayscale image and extract spots’ contour line. Writing programs to calculate contour lines’ fractal dimension and the result shows that laser’s transmission characteristic is less affected by stable atmosphere environment so that the fractal dimension is the smallest. Comparing to the smog of the same class, the influence of vapor on laser’s transmission characteristic is larger; for the fractal dimension is bigger and the spot’s diameter is larger and the energy density is lower. It is feasible to analyze that how different environments affect laser’s transmission characteristic by means of studying on laser spot’s fractal dimension.