Gate-tuned graphene meta-devices for dynamically controlling terahertz wavefronts

Nanophotonics

Ding Fan¹  Ling Xiaohui²  Liu Huanhuan³  Wang Qianqian⁴  Cai Xiaodong⁴  Xiao Shiyi⁴  Li Qiushi⁴  Chen Cong⁵  Liu Tong⁶  He Qiong⁶  Wu Qiong⁶  Jia Min⁶  Zhou Haoyang⁶  Zhang Yuanbo⁶  Zhou Lei⁶ 

[1] China Ship Development and Design Center, Wuhan430064, China;College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang421002, China;Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen518055, China;Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication, Shanghai Institute for Advanced Communication and Data Science, Shanghai University, Shanghai200444, China;School of Electronic Information, Wuhan University, Wuhan430072, China;State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Physics Department, Fudan University, Shanghai200433, China;

关键词: coupled mode theory;    graphene;    metasurfaces;    terahertz;    wavefront manipulations;   

DOI  :  10.1515/nanoph-2021-0801

来源: DOAJ

【 摘 要 】

Dynamical controls on terahertz (THz) wavefronts are crucial for many applications, but available mechanism requests tunable elements with sub-micrometer sizes that are difficult to find in the THz regime. Here, different from the local-tuning mechanism, we propose an alternative approach to construct wavefront-control meta-devices combining specifically designed metasurfaces and globally tuned graphene layers. Coupled-mode-theory (CMT) analyses reveal that graphene serves as a tunable loss to drive the whole meta-device to transit from one functional phase to another passing through an intermediate regime, exhibiting distinct far-field (FF) reflection wavefronts. As a proof of concept, we design/fabricate a graphene meta-device and experimentally demonstrate that it can reflect normally incident THz wave to pre-designed directions with different polarizations under appropriate gating voltages. We finally design a graphene meta-device and numerically demonstrate that it can generate vectorial THz beams with continuously varying polarization distributions upon gating. These findings pave the road to realizing a wide range of THz applications, such as sensing, imaging, and wireless communications.

【 授权许可】

Unknown