基于石墨烯等离激元太赫兹结构的传感及慢光应用  

Sensing and slow light applications of graphene plasmonic terahertz structure

作　　者：杨肖杰 许辉 徐海烨 李铭 于鸿飞 成昱轩 侯海良 陈智全 Yang Xiao-Jie;Xu Hui;Xu Hai-Ye;Li Ming;Yu Hong-Fei;Cheng Yu-Xuan;Hou Hai-Liang;Chen Zhi-Quan(School of Microelectronics and Physics,Hunan University of Technology and Business,Changsha 410205,China;Xiangjiang Laboratory,Changsha 410205,China;School of Intelligent Engineering and Intelligent Manufacturing,Hunan University of Technology and Business,Changsha 410205,China)

机构地区：[1]湖南工商大学微电子与物理学院,长沙410205 [2]湘江实验室,长沙410205 [3]湖南工商大学智能工程与智能制造学院,长沙410205

出　　处：《物理学报》2024年第15期196-207,共12页Acta Physica Sinica

基　　金：湘江实验室重点项目(批准号:23XJ02001);湖南省自然科学基金(批准号:2023JJ40218,2022JJ30201);长沙市自然科学基金(批准号:kq2202298);湖南省教育厅科研基金(批准号:21B0574,21B0556)资助的课题

摘　　要：介绍了一种新型石墨烯太赫兹结构,其周期单元包括一条长石墨烯单层带和两条短石墨烯单层带.通过短石墨烯带所激发的明模式与长石墨烯带所激发的暗模式的相消干涉,该结构产生了等离激元诱导透明效应.利用耦合模理论推导了此效应的产生机理,所得结果与时域有限差分方法的仿真值高度一致.该结构除了具有外部动态可调性之外,还具有十分出色的传感性能,最大灵敏度和品质因子分别可达1.457 THz/RIU和30.5652.此外,提高结构中石墨烯的费米能级和载流子迁移率有助于增强慢光效应,其中载流子迁移率的增强效果尤为明显.当载流子迁移率从0.75 m^(2)/(V⋅s)提高到2.0 m^(2)/(V⋅s)时,结构的群折射率从456增至1010.本研究可为太赫兹波段传感器件和慢光器件的发展提供理论和概念框架.In this work,Ansys FDTD is used to design and simulate a terahertz metamaterial structure based on periodic continuous pattern graphene monolayer,and the high-quality PIT phenomena are obtained by continuously adjusting structural parameters.To validate the designed structure,the simulated transmission curve(reflection curve)obtained is compared with the theoretical transmission curve(reflection curve)derived from coupled-mode theory.It is observed that these two results exhibit a remarkably high degree of overlap.The resonant frequency and Fermi energy reveals a perfect linear correlation between them with the resonant frequency increasing proportionally with Fermi energy increasing.Dynamic tuning of PIT can be realized by adjusting the Fermi energy of graphene.For a more in-depth study of its sensing characteristics,the structure is placed in different environments.As the refractive index of the detection medium increases,the resonant frequency gradually decreases,demonstrating a redshift phenomenon.By manipulating the resonant frequency of the PIT sensor,the selective detection of specific target can berealized.After analyzing the sensitivity and FOM values of the structure,it is found that the maximum sensitivity is 1.457 THz/RIU.At a resonant frequency of 6.8174 THz,FOM reaches 30.5652.In summary,the sensor structure designed in this work has dual frequency sensing characteristics and can be used for dual frequency detection.Moreover,compared with other sensor structures,it demonstrates superior sensing performance.Additionally,in studying the slow light effect of the structure,it is found that as the Fermi energy increases,the group index and phase shift at the transparency window continue to increase.At the Fermi energy of 1.2 eV,the group index reaches a high value of 584.This is because in the PIT phenomenon,transparent peaks are formed due to multimodal coupling.This coupling will significantly improve the dispersion characteristics near the transparent peak,resulting in a large group index near the tra

关 键 词：石墨烯太赫兹结构 等离激元 传感 慢光 

分 类 号：O441.4[理学—电磁学] TQ127.11[理学—物理]