径向偏振多高斯-谢尔模型分数涡旋光束的空间聚焦  

Spatial Focusing of Radially Polarized Multi-Gaussian Schell-Model Fractional Vortex Beam

作　　者：刘磊 李晓明 李辉 吴平辉 Liu Lei;Li Xiaoming;Li Hui;Wu Pinghui(School of Physical Science and Technology,Kunming University,Kunming 650214,Yunnan,China;Key Laboratory of Artificial Microstructures in Yunnan Higher Education Institutions,Kunming University,Kunming 650214,Yunnan,China;Fujian Provincial Key Laboratory for Advanced Micro-Nano Photonics Technology and Devices,Quanzhou Normal University,Quanzhou 362000,Fujian,China)

机构地区：[1]昆明学院物理科学与技术学院,云南昆明650214 [2]昆明学院云南省高校人工微结构重点实验室,云南昆明650214 [3]泉州师范学院福建省先进微纳光子技术与器件重点实验室,福建泉州362000

出　　处：《光学学报(网络版)》2024年第2期32-41,共10页Acta Optica Sinica(Online)

基　　金：福建省自然科学基金面上项目(2022J011102);云南省教育厅科研项目(2020J0514 ZX20220051,ZX20220052);云南省人工微结构重点实验室建设项目(ZX20230258);昆明学院院级团队项目(XJ20230042);昆明学院人才引进项目(YJL2006)

摘　　要：引入一种同时携带涡旋相位和具有特殊空间关联结构的部分相干矢量光束,即径向偏振多高斯-谢尔模型分数涡旋(RP-MGSM-FV)光束,给出了该光束的基本属性,推导了其通过ABCD光学系统后的交叉谱密度解析式;探讨了其涡旋相位项的拓扑荷数大小、符号以及相干宽度对焦平面上光强分布的影响。研究发现:随着横向相干宽度的增大,焦平面上的光强呈现平顶—类高斯—平顶—中空的转变;随着拓扑荷数的增大,焦平面上的空间光强分布出现分离;随着拓扑荷数符号的转换,其空间光强分布图案出现反转。上述结果表明,可以利用分离程度及反转对RP-MGSM-FV光束拓扑荷数的大小、符号进行直观检测。这些结果在自由空间光通信、微观领域的粒子捕获方面有着重要的应用价值。We introduce a unique type of partially coherent light(PCL)that simultaneously carries a vortex phase and exhibits a special spatial correlation structure,known as radially polarized multi-Gaussian Schell-model fractional vortex(RPMGSM-FV)beams.We outline the fundamental requirements for generating such light beams and derive the analytical expression for their cross-spectral density matrix after transmission through ABCD optical systems.We further examine the influence of the topological charge magnitude,sign,and coherence width of its vortex phase component on the intensity distribution at the focal plane.The results indicate that as the coherence width increases,the intensity distribution at the focal plane translates from a flat-top to a Gaussian-like shape,then to a flat-top,and ultimately to a ring pattern.An increase in the topological charge numbers leads to a distinct separation in the spatial distribution of the beam at the focal plane.Additionally,changes in the sign of the topological charge cause an inversion in the spatial distribution pattern,allowing for the detection of both the magnitude and sign of the topological charge in RP-MGSM-FV beams.These findings are significantly valuable in applications such as free-space optical communications and particle trapping in micro domains.

关 键 词：光场调控 拓扑荷数 部分相干光 

分 类 号：O436[机械工程—光学工程]