基于几何相位的超表面产生宽带太赫兹涡旋波束的设计
Design of wideband terahertz vortex beam generation using geometric phase metasurfaces
张莉 1孙俊1
作者信息
- 1. 昆明理工大学信息工程与自动化学院,昆明 650000
- 折叠
摘要
为克服太赫兹涡旋波束存在带宽窄、效率低下等缺点,提出了一种基于几何相位的单层透射型超薄超表面,通过对超表面单元结构的设计和排布实现了宽带范围内太赫兹涡旋波的产生.该超表面单元由表层双C型金属环和底层介质层组成.利用几何相位原理,通过旋转金属结构,可以控制交叉极化透射光在宽频带内保持相同透射系数的前提下对其透射相位进行调控.通过对单元结构进行旋转编码,可以形成宽频带内用以产生不同拓扑荷数涡旋波束的编码超表面.仿真结果表明,在1.38～1.92 THz宽频带内,产生了拓扑荷数为l=±1两种模态的涡旋波束,且最大交叉极化透射效率为23％,接近单层结构的理论极限值.
Abstract
This paper presents a single-layer transmission-type metasurface based on geometric phase,which ena-bles the generation of broadband Terahertz vortex waves through the design and arrangement of metasurface unit struc-tures.The metasurface unit consists of a top layer with dual C-shaped metal rings and a bottom dielectric layer.By uti-lizing the geometric phase principle and rotating the metal structures,the phase of cross-polarized transmitted light can be controlled while maintaining the same transmission coefficient over a wide frequency range.By encoding the unit structures with rotation,an encoded metasurface is formed capable of generating vortex beams with different topological charges in a wide frequency band.Simulation results demonstrate the generation of vortex beams with topological char-ges of l=±1 in the frequency range of 1.38-1.92 THz,with a maximum cross-polarization transmission efficiency of 23％.close to the theoretical limit of a single-layer structure.
关键词
几何相位/超表面/宽带/太赫兹/涡旋波束Key words
geometric phase/metasurface/broadband/Terahertz/vortex引用本文复制引用
出版年
2024
NETL
NSTL
万方数据