摘要
The advancement of terahertz technology in recent years and its applications in various fields lead to an urgent need for functional terahertz components,among which a terahertz switch is one example of the most importance because it provides an effective interface between terahertz signals and information in another physical quantity.To date many types of terahertz switches have been investigated mainly in the form of metamaterials made from metallic structures and optically-active medium.However,these reported terahertz switches usually suffer from an inferior performance,e.g.,requiring a high pump laser power density due to a low quality factor of the metallic metamaterial resonances.In this paper,we report and numerically investigate a symmetry-broken silicon disk based terahertz resonator array which exhibits one resonance with ultrahigh quality factor for normal incidence of the terahertz radiations.This resonance,which can never be excited for regular circular Si disks,can help to realize a superior terahertz switch with which only an ultra-low optical pump power density is required to modify the free carrier concentration in Si and its refractive index in the terahertz band.Our findings demonstrate that to realize a high terahertz transmittance change from 0 to above 50%,the required optical pump power density is more than 3 orders of magnitude smaller than that required for a split-ring resonator(SRR)based terahertz switch reported in the literature.
作者
Zhanghua Han
Hui Jiang
Zhiyong Tan
Juncheng Cao
Yangjian Cai
韩张华;姜辉;谭智勇;曹俊诚;蔡阳健(Shandong Provincial Key Laboratory of Optics and Photonic Devices,School of Physics and Electronics,Shandong Normal University,Jinan 250358,China;Key Laboratory of Terahertz Solid-State Technology,Shanghai Institute of Microsystems and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)
基金
the National Key R&D Program of China(Grant No.2017YFA0701005)
the National Natural Science Foundation of China(Grant Nos.11974221,91750201,61927813,and 61775229)
Z.Han also acknowledges the support from the Taishan Scholar Program of Shandong Province,China(Grant No.tsqn201909079)
Zhejiang Provincial Natural Science Foundation of China(Grant No.LY15F050008).
