用于基于石墨烯的有源超颖透镜的增强太赫兹聚焦

Enhanced terahertz focusing for a graphene-enabled active metalens.

作者信息

Huang Jianzhou, Guan Hongyu, Hu Bin, Wang Guocui, Liu Weiguang, Wang Zongyuan, Liu Juan, Zhang Yan, Wang Yongtian

出版信息

Opt Express. 2020 Nov 9;28(23):35179-35191. doi: 10.1364/OE.409746.

Abstract

Graphene-based terahertz (THz) metasurfaces have the advantages of ultra-small thickness, electrical tunability, and fast tuning speed. However, many such structures suffer low efficiency, especially for transmissive devices. Here we propose a hybrid structure for focusing THz waves with tunability and enhanced focusing efficiency, which is composed of a graphene-loaded metallic metasurface sandwiched by two mutually orthogonal gratings. Experimental results show that due to the multi-reflection between the metasurface layer and the grating layer, the focusing efficiency is enhanced by 1.8 times, and the focal length of the metalens is increased by 0.61 mm when the applied gate voltage on the graphene is increased from 0 V to 1.4 V. We hope the proposed structure may open a new avenue for reconfigurable THz metasurfaces with high efficiencies.

摘要

基于石墨烯的太赫兹（THz）超表面具有厚度超小、电可调性和快速调谐速度等优点。然而，许多此类结构效率较低，尤其是对于透射式器件。在此，我们提出一种用于聚焦太赫兹波的具有可调性和增强聚焦效率的混合结构，它由夹在两个相互正交光栅之间的负载石墨烯的金属超表面组成。实验结果表明，由于超表面层和光栅层之间的多次反射，当施加在石墨烯上的栅极电压从0 V增加到1.4 V时，聚焦效率提高了1.8倍，金属透镜的焦距增加了0.61 mm。我们希望所提出的结构可为高效可重构太赫兹超表面开辟一条新途径。