闪耀型亚波长光栅透镜的柱矢量光聚焦优化和调控  

Focusing Optimization and Control of Cylindrical Vector Beams with Blazed Subwavelength Grating Lens

作　　者：王俊[1] 许吉[1] 李胜 迟甜甜 姚晗 张柏富 刘宁[1] Wang Jun;Xu Ji;Li Sheng;Chi Tiantian;Yao Han;Zhang Baifu;Liu Ning(College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology),Nanjing University of Posts and Telecommunications,Nanjing 210023,Jiangsu,China;School of Electronic and Optical Engineering,Nanjing University of Science and Technology,Nanjing 210023,Jiangsu,China)

机构地区：[1]南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院,江苏南京210023 [2]南京理工大学电子工程与光电技术学院,江苏南京210023

出　　处：《光学学报》2024年第2期104-111,共8页Acta Optica Sinica

基　　金：国家自然科学基金(11404170,61505083);南京邮电大学校级科研基金(NY219045)。

摘　　要：柱矢量光束的紧聚焦在光学微操纵、光学存储、激光微加工、超分辨率成像和粒子加速等领域发挥着重要作用。亚波长光栅平凹透镜对柱矢量光束的紧聚焦的能力仍有提升空间,本文利用闪耀结构将光的能量从零级转移并集中到-1级,对亚波长光栅平凹透镜的聚焦性能进行优化。提高了透镜的衍射效率,增强了焦场的能量。通过调整高斯径向偏振光的形状参数,改变入射光振幅及入射区域半径实现对焦场能量的动态调控。进一步地,调控柱矢量光束的偏振组分能够直接有效地横向调制焦场,获得多样化形貌的焦斑。本文的优化手段对于其他光栅透镜也具有参考意义,该研究结果在超分辨率成像以及光场调控等领域具有潜在的应用价值。Objective The amplitude and polarization of cylindrical vector beams(CVBs)are distributed cylindrically and symmetrically,and the tight CVBs focusing plays an important role in optical micromanipulation,optical storage,laser micromachining,super-resolution imaging,particle acceleration,and other fields.At present,various focusing methods have been developed,such as traditional lenses,plasmonic lenses,negative refractive photonic crystal lenses,parabolic mirrors,and meta-lenses.However,there are limitations including diffraction limit,polarization dependence,and complex preparation.Subwavelength grating lens based on−1st order diffraction can achieve tight focusing of radial and azimuthal polarized lights spontaneously,breaking through the diffraction limit and realizing flexible focal field manipulation.Despite these advantages,the energy efficiency of its focal field still deserves further improvement.Therefore,we explore and propose a structural optimization scheme for a blazed subwavelength grating lens that can increase the energy ratio of−1st order diffracted light energy to enhance the focal field energy.Method We employ the full vector calculation of electromagnetic field(COMSOL Multiphysics software)based on the finite element method(FEM)to carry out specific research.The blazed structure is located on each grating step with a consistent height,and the overall lens structure is a uniform dielectric GaN.Firstly,an equivalent triangular prism model is built to verify the enhancement effect of the blazed structure on−1st order diffraction.Next,the energy and morphology changes of the focal field before and after modifying the blazed structure are compared,and the influence of the height,number,and location of blazed structures on the focal field is analyzed.Finally,the dynamic manipulation effect of the incident light amplitude distribution and polarization components on the focal field energy and morphology is studied.Results and discussion In the equivalent prism model,adding the blazed gratings sign

关 键 词：亚波长光栅透镜 柱矢量光束 闪耀结构 聚焦 调控 

分 类 号：O436[机械工程—光学工程]