左/右圆极化波操控的多功能太赫兹超表面  

Multifunctional Terahertz Metasurface Controlled by Left/Right Circularly Polarized Waves

作　　者：蒋铭阳 李九生[1] 郭风雷 JIANG Ming-yang;LI Jiu-sheng;GUO Feng-lei(Center for THz Research,China Jiliang University,Hangzhou 310018,China)

机构地区：[1]中国计量大学太赫兹研究所,浙江杭州310018

出　　处：《光谱学与光谱分析》2024年第12期3371-3377,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(62271460)资助。

摘　　要：太赫兹波是指频率位于0.1~10 THz之间的电磁波,介于微波和红外之间,具有穿透力强、分辨率高、无电离辐射等优势,在安全检测、医学诊断、材料分析等领域有广泛应用前景。太赫兹技术发展与应用对太赫兹波多功能调控器件的需求日益增长,传统介质在太赫兹波段响应微弱,超表面因其能够在波长尺度对太赫兹波进行调控,而且在加工和设计方面具有低成本、小体积等优势,受到研究人员广泛关注。目前已报道超表面太赫兹功能器件,或多或少存在着功能单一,而且受单一偏振波限制。当前,研究人员提出方案主要是改变亚波长超表面结构的几何形态和排列方式引入传输相位或通过旋转单元结构引入几何相位实现对电磁波参数调控,但是单种调控方式仍然存在可调谐性差等问题,因此设计基于传输相位和几何相位理论协同调控的超表面电场调控器件显得更具前瞻性和意义。引入一种全新对角双十字结构超表面,该超表面单元结构由顶层金属图案、中间介质层和底层金属板组成,结合传输相位与几何相位协同作用,完成对左圆偏振波和右圆偏振波独立调控。在频率为1.1 THz的左/右圆偏振波入射时,该超表面展现出多种功能,包括不同拓扑荷数的涡旋波束、波束分束、涡旋波分束、聚焦波束等。这种创新结构设计为多功能、多偏振的太赫兹调控器件研究提供了崭新的思路,为太赫兹无线通信领域的应用场景提供了潜在的可能性,同时也为太赫兹技术的不断发展提供了强大的推动力。在未来的研究中,可以通过改变超表面尺寸将其进一步拓展到微波和光学领域。Terahertz waves are electromagnetic waves with frequencies between 0.1 and 10 THz,between microwave and infrared,with strong penetration,high resolution,no ionizing radiation,and other advantages,which have a wide range of application prospects in the fields of safety detection,medical diagnosis,material analysis and so on.The demand for Terahertz technology development and application of terahertz wave multifunctional modulation devices is growing.The traditional medium in the terahertz band response is weak;the metasurface,because of its ability to modulate the terahertz wave at the wavelength scale and in the processing and design of low-cost,small volume and other advantages by the researchers are widely concerned.Terahertz functional devices with metasurface have been reported to have more or less single functions and are limited by a single polarisation wave.Researchers propose that the program is mainly to change the geometric morphology and arrangement of the sub-wavelength metasurface structure to introduce the transmission phase or the geometric phase through the rotating unit structure to achieve the electromagnetic wave parameter tuning.However,a single tuning method still exists due to poor tunability and so on,and therefore,the design of the metasurface electric field tuning device based on the synergistic tuning of the transmission and geometric phase theory seems more prospective and meaningful.In this paper,a new diagonal double-cross structure metasurface is introduced,which consists of a top metal pattern,an intermediate dielectric layer,and a bottom metal plate and combines the synergistic effect of the transmission phase and geometrical phase to complete the independent tuning of the left circularly polarised wave and the right circularly polarised wave.At the incident of left/right circularly polarised waves with a frequency of 1.1 THz,the metasurface exhibits a variety of functions,including vortex beams,beam splitting,vortex wave splitting,and focusing beams with different topological char

关 键 词：太赫兹超表面 圆偏振波 传输相位 几何相位 太赫兹分束 

分 类 号：O436[机械工程—光学工程]