High-efficiency threshold-less Cherenkov radiation generation by a graphene hyperbolic grating in the terahertz band

被引：20

作者：

Zhang, Xiaoqiuyan ^{[1
,2
]}

Hu, Min ^{[1
,2
]}

Zhang, Zhuocheng ^{[1
,2
]}

Wang, Yueying ^{[1
,2
]}

Zhang, Tianyu ^{[1
,2
]}

Xu, Xingxing ^{[1
,2
]}

Zhao, Tao ^{[1
,2
]}

Wu, Zhenhua ^{[1
,2
]}

Zhong, Renbin ^{[1
,2
]}

Liu, Diwei ^{[1
,2
]}

Wei, Yanyu ^{[1
,2
]}

Gong, Yubin ^{[1
,2
]}

Liu, Shenggang ^{[1
,2
]}

机构：

[1] Univ Elect Sci & Technol China, Sch Elect Sci & Engn, Terahertz Res Ctr, Chengdu 610054, Peoples R China

[2] Minist Educ, Key Lab Terahertz Technol, Chengdu 610054, Peoples R China

来源：

CARBON | 2021年 / 183卷

基金：

中国国家自然科学基金;

关键词：

Cherenkov; Terahertz; Graphene hyperbolic grating; METAMATERIALS; POLARITONS;

D O I：

10.1016/j.carbon.2021.06.091

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Cherenkov radiation (CR), generated when charged particles move faster than the light velocity in a medium, is an important radiation phenomenon of electron-matter interactions. Here, we demonstrate high-efficiency threshold-less in-plane CR generation in the terahertz (THz) band using a periodic graphene hyperbolic grating (GHG) structure. Our theoretical and numerical analyses proved that the phase velocity in the GHG is always lower than the electron velocity; this is owing to the graphene hyperbolic plasmon polaritons induced biaxially in the GHG. Based on the simulation results, the power of the in-plane CR in the GHG is nearly two orders of magnitude larger than that of the out-of-plane CR in the conventional graphene-dielectric hyperbolic metamaterial bulk. A full electromagnetic dipole source mode is employed to describe the fascinating in-plane hyperbolic-like spatial dispersion in the GHG. Moreover, by adjusting the size of the GHG, graphene chemical potential, and free electron energy, the CR angle and intensity can be completely controlled. This framework provides a new way to develop high-efficiency, threshold-less, and tunable CR sources in the THz range with excellent adjustability and serves as a general approach applicable to other polariton types active in a wide range of materials, such as phonon- and exciton-polaritons. (C) 2021 Elsevier Ltd. All rights reserved.

引用

页码：225 / 231

页数：7