双光束任意入射各向异性涂层球的散射特性  

Electromagnetic Scattering of Dual Gaussian Beams by an Anisotropic Coated Sphere

作　　者：白靖 高宇 葛城显 吴振森[3] Bai Jing;Gao Yu;Ge Chengxian;Wu Zhensen(School of Electronic Engineering,Xi'an University of Posts&Telecommunications,Xi'an 710121,Shaanxi,China;The 39th Research Institute of China Electronics Technology Corporation,Xi'an 710065,Shaanxi,China;School of Physics,Xidian University,Xi'an 710071,Shaanxi,China)

机构地区：[1]西安邮电大学电子工程学院,陕西西安710121 [2]中国电子科技集团公司第三十九研究所,陕西西安710065 [3]西安电子科技大学物理学院,陕西西安710071

出　　处：《光学学报》2023年第23期270-279,共10页Acta Optica Sinica

基　　金：国家自然科学基金(62001377,62101445,61571355,61601355,61308025);陕西省自然科学基金(2023-JC-QN-0657,2023-JC-QN-0774,2022KJXX-95,2020JQ-843);西安市科协青年人才托举计划项目(959202313013)。

摘　　要：基于广义洛伦兹-米理论,研究两个聚焦的高斯光束沿着任意方向入射单轴各向异性涂层球的散射特性。基于球矢量波函数的正交特性,推导得到双高斯光束的球矢量波函数展开表达式。通过引入傅里叶变换,求解得到各向异性涂层区域内的电磁场展开式,将涂层球各区域的电磁场用球矢量波函数展开,再结合边界条件,得到沿任意方向传播的双高斯光束入射到涂层球的散射系数和雷达散射截面。数值模拟了雷达散射截面随散射角变化的分布,将单轴各向异性涂层球退化为单轴各向异性球时的散射结果与文献进行对比,结果十分吻合。分析双光束的入射角、粒子内半径、涂层厚度与内半径的比值、电和磁各向异性对散射强度及其散射角分布的影响。该理论和数值分析能够为激光对涂层颗粒的探测、散射以及光学操作提供有益帮助。Objective Since Lorenz-Mie theory was put forward,the scattering and absorption of electromagnetic waves by tiny particles have been widely studied.In recent years,coated media spheres have caught extensive attention from scholars due to their wide applications in various fields,including radar cross section(RCS),nanomaterials,and spectroscopy.Owing to different values of dielectric constants and magnetic permeability in various directions of anisotropic materials,significant changes occur in the internal electromagnetic field of a uniaxial anisotropic coated(UAC)sphere when a laser is incident from different directions,which significantly influences its surface RCS.The previous literature mainly studies the electromagnetic scattering of a single planar wave and a single Gaussian beam on coated spheres.However,in the optical manipulation of small particles,it is easier to employ two or more beams to capture and manipulate the particles than adopting only one laser beam.Therefore,it is essential to investigate the electromagnetic scattering problem of a UAC sphere by dual focused Gaussian beams for achieving optical manipulation of coated spheres.Methods Based on the generalized Lorenz-Mie theory(GLMT),we study the scattering characteristics of a UAC sphere which is induced by two focused Gaussian beams with arbitrary directions.According to the orthogonality of spherical vector wave functions(SVWFs),the expression of dual Gaussian beam in terms of SVWFs is derived.By introducing the Fourier transform,the electromagnetic field expansion in the anisotropic coated area is obtained.The electromagnetic fields in each region of the UAC sphere are expanded in terms of the SVWFs,and by combining the boundary conditions,the scattering coefficients and the radar scattering crosssection of uniaxial anisotropic coated sphere illuminated by two Gaussian beams are obtained.Results and Discussions The effects of the incident angle of dual beams,particle inner diameter,the ratio of coating thickness to the inner diameter,electri

关 键 词：散射 球矢量波函数 双光束 单轴各向异性涂层球 

分 类 号：O433[机械工程—光学工程] O432[理学—光学] O451[理学—物理]