深度湍流条件下激光往返传输漂移特性的实验探究  

Experimental study on the laser beam wander characteristics of fold path propagation under deep turbulence condition

作　　者：李昕淼 梅海平 张骏昕 李艳玲 邓涵凌 陶志炜 Li Xinmiao;Mei Haiping;Zhang Junxin;Li Yanling;Deng Hanling;Tao Zhiwei(Key Laboratory of Atmospheric Optics,Anhui Institute of Optics and Fine Mechanics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;Science Island Branch,Graduate School of University of Science and Technology of China,Hefei 230026,China;Advanced Laser Technology Laboratory of Anhui Province,Hefei 230037,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]中国科学技术大学研究生院科学岛分院,安徽合肥230026 [3]先进激光技术安徽省实验室,安徽合肥230037

出　　处：《红外与激光工程》2024年第5期173-182,共10页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(62301530,12302514);中国科学院合肥物质科学研究院院长基金项目(YZJJ2023QN05)。

摘　　要：为探究深度湍流条件下激光往返传输的漂移特性,基于修正的Rytov理论,推导了深度湍流条件下光束漂移角方差表达式。搭建了折返路径激光成像探测系统,实验获取了1 km和7 km传输路径上不同时段激光光斑的回波图像和大气相干长度。利用回波图像计算了漂移角均方差及其各向异性因子并与理论对比。结果表明:漂移角均方差和大气相干长度随时间变化具有明显周期性,两者变化同步,但趋势相反。1 km传输路径上,漂移角均方差在2~24μrad之间波动。而7 km传输路径上漂移角均方差在4~26μrad之间波动。通过对比Kolmogorov理论、Von Karman理论、Exponential理论和修正的Rytov理论模型下漂移角均方差与实测值的相对偏差发现:基于Von Karman理论的模型与1 km传输路径上漂移角均方差的实测值更为吻合,平均相对偏差约为18.20%,基于修正Rytov折射率功率谱理论的模型与7 km传输路径上漂移角均方差的实测值更为吻合,平均相对偏差约为21.09%。在1 km和7 km传输路径上,漂移特性均随着大气相干长度的减小而趋于各向同性。相关实验结果进一步揭示了深度湍流下往返路径传输激光漂移的机理,对于长距离空间光通信维持稳定通信链路具有一定参考价值。Objective Affected by atmospheric turbulence,the laser produces scintillation,beam wander,and fluctuation of the angle-of-arrival.Beam wander causes the beam to deviate from the target detector and reduces the efficiency of energy transmission,affecting applications such as laser tracking,laser positioning,and optical communications,especially over long distances.Under weak fluctuation conditions,the traditional theory of laser atmospheric propagation can be relatively accurately described.There is still a lack of reliable experimental evidence as to whether the theory is accurate in several kilometers of propagation under deep turbulence near the ground.Most of the current theories and simulations are based on existing assumptions,and there is often a certain deviation from the actual situation,especially under deep turbulence,where the theory is not yet perfect.The distances of the beam wander experiments are all relatively short and do not support the theory associated with long distance propagation.Therefore,it is of great significance to summarize the relevant theories of beam wander under deep turbulence and carry out long-distance laser propagation experiments to reveal the differences between the theoretical model and the reality.The relevant data provide an experimental basis for evaluating the model accuracy or error,and optimizing or correcting the model.Methods Firstly,the theory of the variance of the drift angle for different refractive index power spectral models in the moderately to strongly turbulent region is summarized and derived.Then,the experiment system of fold path laser propagation(Fig.1)was built to collect the echo spot data using a large-aperture telescope and the atmospheric coherence length by an atmospheric coherence length meter.Four days of experiments were carried out on the 1 km propagation path and three days on a 7 km propagation path.The daily variation of the standard deviation of drift angle is obtained by calculating the echo spot data and studied in comparison with the th

关 键 词：深度湍流 折返路径 激光光斑 漂移角均方差 大气相干长度 

分 类 号：O436[机械工程—光学工程]