Optically controlled dielectric metasurfaces for dynamic dual-mode modulation on terahertz waves  

作　　者：Haoyang Zhou Sheng Zhang Shunjia Wang Yao Yao Qingnan Cai Jing Lin Xiaoying Zheng Zhuo Wang Zhensheng Tao Qiong He Lei Zhou 

机构地区：[1]Fudan University,Key Laboratory of Micro and Nano Photonic Structures(Ministry of Education)and Department of Physics,State Key Laboratory of Surface Physics,Shanghai,China

出　　处：《Advanced Photonics》2023年第2期70-79,共10页先进光子学（英文）

基　　金：the National Key Research and Development Program of China(Grant No.2022YFA1404700);the National Natural Science Foundation of China(Grant Nos.12221004,11734007,and 11874121);the Natural Science Foundation of Shanghai(Grant Nos.20JC1414601 and 19JC1410900)。

摘　　要：Dynamically controlling terahertz(THz)waves with an ultracompact device is highly desired,but previously realized tunable devices are bulky in size and/or exhibit limited light-tuning functionalities.Here,we experimentally demonstrate dynamic modulation on THz waves with a dielectric metasurface in modeselective or mode-unselective manners through pumping the system at different optical wavelengths.Quasi-normal-mode theory reveals that the physics is governed by the spatial overlap between wave functions of resonant modes and regions inside resonators perturbed by pump laser excitation at different wavelengths.We further design/fabricate a dielectric metasurface and experimentally demonstrate that it can dynamically control the polarization state of incident THz waves,dictated by the strength and wavelength of the pumping light.We finally numerically demonstrate pump wavelength-controlled optical information encryption based on a carefully designed dielectric metasurface.Our studies reveal that pump light wavelength can be a new external knob to dynamically control THz waves,which may inspire many tunable metadevices with diversified functionalities.

关 键 词：dynamic metasurfaces TERAHERTZ quasi-normal-mode theory optical pumping. 

分 类 号：TB34[一般工业技术—材料科学与工程] O441.4[理学—电磁学]