聚焦高斯光束湍流大气传输的定标模型  

Scale Model of Focused Gaussian Beam Propagating in Turbulent Atmosphere

作　　者：陈小威 朱文越[1,2] 钱仙妹 武鹏飞[1,2] 青春 孙刚 魏合理 翁宁泉 崔询 Chen Xiaowei;Zhu Wenyue;Qian Xianmei;Wu Pengfei;Qing Chun;Sun Gang;Wei Heli;Weng Ningquan;Cui Xun(Key Laboratory of Atmospheric Optics,Anhui Institute of Optics and Fine Mechanics,HFIPS,Chinese Academy of Sciences,Hefei 230031,Anhui,China;Advanced Laser Technology Laboratory of Anhui Province,Hefei 230037,Anhui,China;School of Environmental Science and Optoelectronic Technology,University of Science and Technology of China,Hefei 230026,Anhui,China)

机构地区：[1]中国科学院合肥物质科学研究院安徽光学精密机械研究所中国科学院大气光学重点实验室,安徽合肥230031 [2]先进激光技术安徽省实验室,安徽合肥230037 [3]中国科学技术大学环境科学与光电技术学院,安徽合肥230026

出　　处：《中国激光》2023年第22期101-110,共10页Chinese Journal of Lasers

基　　金：科工局国防基础科研计划(JCKY2019130D021);脉冲功率激光技术国家重点实验室主任基金(SKL2020ZR08);中国科学院合肥研究院院长基金(YZJJ2021QN08)。

摘　　要：为实现激光湍流大气传输效应的快速评估,采用数值仿真方法研究高斯光束远场长曝光光斑的定标规律。首先,对理想光束真空衍射和湍流扩展效应分别定标,结果表明光源截断强弱影响远场有效半径大小。然后,考虑衍射、初始像差、平台抖动和湍流扩展的相互作用,改进了半径平方加和假设,建立了远场63.2%环围功率半径和平均光强的定标规律模型。特别地,对于截断因子为2√2的高斯光束,在实际激光系统特性、常用光学湍流廓线、地对空传输路径组成的参数空间中开展了数值仿真,利用遗传算法确定了模型的标度指数。结果表明基于改进的半径平方加和方法所建立的定标规律模型精度有了显著提升。定标规律模型与数值仿真的结果对比表明,真空传输远场半径的平均相对偏差为1.55%,湍流大气传输远场半径和平均光强的平均相对偏差分别为1.92%和3.80%。Objective Laser beams propagating in the atmosphere suffer from adverse effects due to the atmospheric optical characteristics and laser system features,which broaden the beam radius and weaken the encircled mean intensity.The wave-optics-based fourdimensional codes work with redundant inputs and slow speed,failing to meet the requirements of rapid assessment for practical applications.Researchers have made efforts to develop new methods,holding reasonable accuracy,calculating quickly and easily,without consideration of the mesh size and computational stability as wave optics programs.Integrated with characteristic parameters of laser system and atmosphere,the scale law has received much attention and is widely used in system design and applications with lots of computation.Current laser beam propagation scale law is based on radius-square-sum(RSS)assumption,meaning that the resulting far-field radius is the root of the sum of radii squared of the individual effect contributions.The RSS assumption lacks scientific foundation and may bring some errors in use.Besides,though the accuracy of scale law is crucial for reliable analysis,few reports on the accuracy of scale models have been released.Furthermore,previous attention was focused mainly on flat-top source,thus the effect of new features of Gaussian source,such as truncating extent,on far-field spot has not been well studied.Methods Theoretical analysis and numerical simulations are used to build the scale model.Analytical expression of 63.2% encircled power radius in the far-field of infinite Gaussian source is deduced on the basis of Huygens-Fresnel principle,showing that the radius is a function of wavelength,distance and aperture.When the Gaussian source is truncated,split-step wave optics simulations are used to obtain the far-field radii corresponding to 63.2% and 86.5% encircled power.Referring to the analytical expression of infinite Gaussian source,a radius scale function for truncated Gaussian source is built,and the scale exponents are given for dif

关 键 词：大气光学 大气传输 高斯光束 定标规律 精度 

分 类 号：O439[机械工程—光学工程] TN012[理学—光学]