基于液晶空间光调制器的附面层效应模拟  

Boundary Layer Effect Simulation Based on Liquid Crystal Spatial Light Modulator

作　　者：景刚 刘智[2] 林鹏 刘树通 蒋青芳 JING Gang;LIU Zhi;LIN Peng;LIU Shutong;JIANG Qingfang(School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun 130022,China;National and Local Joint Engineering Research Center of Space Optoelectronic Technology,Changchun University of Science and Technology,Changchun 130022,China;School of Electronic Information Engineering,Changchun University of Science and Technology,Changchun 130022,China)

机构地区：[1]长春理工大学光电工程学院,长春130022 [2]长春理工大学空间光电技术国家地方联合工程研究中心,长春130022 [3]长春理工大学电子信息工程学院,长春130022

出　　处：《光子学报》2024年第2期232-243,共12页Acta Photonica Sinica

基　　金：国家自然科学基金叶企孙科学基金(No.U2141231)。

摘　　要：为了给航空动平台激光通信的附面层效应校正系统提供验证条件,设计了一种基于液晶空间光调制器来模拟附面层效应的模拟器。首先,从几何光学的角度分析附面层效应,将其等效为负透镜。然后,利用计算机对不同飞行条件下附面层效应与等效负透镜焦距之间的关系进行数值分析仿真。之后在液晶空间光调制器上导入不同焦距透镜的相位灰度图以实现变焦透镜的功能,通过改变变焦透镜的焦距来模拟航空平台不同飞行条件下的附面层效应。最后通过实验验证模拟的准确性,在环境温度下,模拟附面层效应的液晶空间光调制器得到的光斑图像由红外相机拍摄,之后进行图像处理分析实际光斑大小,并与理论计算光斑大小比较,得出误差曲线图。研究结果显示,基于液晶空间光调制器模拟附面层效应引起散斑效应的理论光斑大小与实际光斑大小的均方根误差为0.04375,验证了所提出的方法的可行性和有效性。With the advancement of flight conditions for aerospace platforms,the impact of the boundary layer effect on space laser communication transmission is also growing.In order to reduce the influence of the boundary layer effect,corresponding correction methods must be studied.To provide verification conditions for the boundary layer effect correction system of laser communication on aerospace platforms,a simulator based on the Liquid Crystal Spatial Light Modulator(LC-SLM)was designed to simulate the boundary layer effect.This article first analyzes it from the perspective of geometric optics.It is assumed that the boundary layer is a thin layer(the inner and outer diameters are equal).The refractive index of the free flow is different from the refractive index of the boundary layer.Substituting them into the focal length formula of the lens makes it equivalent to a negative lens.Under different flight conditions,the focal length of the equivalent lens is different.Then use computer software to perform numerical analysis.Setting the wall curvature radius of the aerodynamic platform as 190 mm and the flight Mach number range as 0~5 Ma,in the case of troposphere(0~11 km),lower stratosphere(11~20 km),and upper stratosphere(20~32 km),the relationship curves are obtained between the Mach number,flight altitude,and the equivalent focal length of the negative lens representing the boundary layer effect.Research shows that as the Mach number increases,the equivalent focal length of the negative lens decreases,indicating a greater impact on the communication beam.Especially when the Mach number is small,the equivalent lens focal length changes more significantly with the Mach number.After that,the changes stabilized.In terms of flight altitude,the higher the flight altitude,the thinner the air and the lower the temperature,the boundary layer effect decreases accordingly until the equivalent lens focal length value approaches infinity,at which point it can basically be ignored.Based on the above analysis,the following is an

关 键 词：光通信 附面层效应 光斑分析 液晶空间光调制器 液晶变焦透镜 模拟器 

分 类 号：TN929.1[电子电信—通信与信息系统]