基于介质超构透镜的光学扩束器和缩束器的设计及应用  

Design and Application of Beam Expander and Reducer Based on Dielectric Metalens

作　　者：柳文彪 杜波波 马亦刚 杨元通 王玺莹 卢锦贤 张磊[1,2] 张彦鹏 LIU Wenbiao;DU Bobo;MA Yigang;YANG Yuantong;WANG Xiying;LU Jinxian;ZHANG Lei;ZHANG Yanpeng(School of Electronic Science and Engineering,Xi′an Jiaotong University,Xi′an 710049,China;Key Laboratory of Physical Electronics and Devices of Ministry of Education,Xi′an Jiaotong University,Xi′an 710049,China)

机构地区：[1]西安交通大学电子科学与工程学院,西安710049 [2]西安交通大学电子物理与器件教育部重点实验室,西安710049

出　　处：《光子学报》2024年第12期12-22,共11页Acta Photonica Sinica

基　　金：国家自然科学基金(No.62105257);中央高校基本科研业务费(No.xxj032023006);国家级大学生创新创业训练计划项目(No.S202310698574)。

摘　　要：为了实现高效光束调控,提出了一种基于介质超构表面技术的光学扩束器和缩束器,并通过时域有限差分法(FDTD)进行了仿真验证。该超构表面选用单一材料铌酸锂(LiNbO_(3)),设计透镜单元结构,实现对光束的有效操控。仿真结果显示,设计的2倍和4倍超构表面扩束器、缩束器能够高效地实现光束的扩束和缩束,并保证出射光束的精度和质量,光束透过率达到58%。此外,该扩束、缩束器对入射光波长,入射角度有较好的容差能力。With the rapid advancements in optical technologies,there are increasing demands for precise light manipulation,e.g.,beam expansions and reductions.Traditional optical components are often limited by their bulky,heavy,and expensive nature,which poses significant challenges to the system efficiency and integration.Additionally,two-dimensional metamaterials,i.e.,the metasurfaces consisting of sub-wavelength functional structures allow to manipulate optical beam with unprecedented freedoms on micro-scale chip.Upon the development of metasurfaces,a plenty of optical components were miniaturized and witnessed success in applications ranging from lenses,holography,coloration,polarization control,spectroscopy,and many more.However,the existing metasurfaces typically rely on combinations of various dielectric materials on one single chip.This feature not only leads to the complicated fabrication process but also limits their application robustness.In order to address these limitations,this study introduces an alternative approach to conduct a metalens by designing a monolithic dielectric metasurface using lithium niobate(LiNbO_(3),LN).LN was selected because of its extraordinary optical properties,including wide-band transparency for transmissive operations and high refractive index to localized optical field.Furthermore,beam expanders and reducers based on the monolithic dielectric metalenses were proposed and investigated numerically.The monolithic dielectric metalens was designed based on the theory of the Generalized Laws of Reflection and Refraction,in which way the phase delay of light through the LN metasurface was adjusted by altering the size of the cylindrical LN unit cell.Then,varied sizes of the LN nano-pillars were arranged according to the required phase profile to enable the metalens functionality.In detail,a series of Finite-Difference Time-Domain(FDTD)simulations were performed and the geometrical parameters of the unit cell providing required phase delay for light focusing were then optimized.The featur

关 键 词：超构透镜 介质超构表面 光束扩束器 光束缩束器 时域有限差分法 

分 类 号：TN256[电子电信—物理电子学]