基于狄拉克半金属的混合等离子体宽带可调谐太赫兹波导  

Tunable and Broadband Hybrid Plasmonic Terahertz Waveguide Based on 3D Dirac Semimetals

作　　者：戴子杰 赖隆浩 潘尔怡 叶云霞[1] 陈明阳[1] 黄志明[2] Dai Zijie;Lai Longhao;Pan Eryi;Ye Yunxia;Chen Mingyang;Huang Zhiming(School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China;State Key Laboratory of Infrared Physics,Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200083,China)

机构地区：[1]江苏大学机械工程学院,江苏镇江212013 [2]中国科学院上海技术物理研究所红外物理国家重点实验室,上海200083

出　　处：《中国激光》2024年第23期168-175,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(62205131);江苏省自然科学基金青年项目(BK20220519);红外物理国家重点实验室开放课题(SITP-NLIST-YB-2022-13);江苏省高等学校基础科学(自然科学)研究项目(22KJB140002);中国博士后科学基金(2022M721378)。

摘　　要：设计了一种基于三维狄拉克半金属(DSM)的可调谐混合等离子体太赫兹波导器件,研究了结构几何参数和DSM费米能级对太赫兹波传输特性的影响规律。仿真结果表明,随着波导介质间隙的增加,有效模式折射率的实部和传播长度均增加;随着波导介质长度的增加,有效模式折射率增大,而传输损耗减小。当DSM费米能级由0.01 eV增加到0.10 eV时,波导的传播长度在3.33×10~2~1.72×10^(4)μm范围内可调,最大调制深度达到了98.06%,且工作带宽覆盖0.5~2.0 THz。研究结果对于理解混合等离子体波导的调谐机制以及相关太赫兹器件的设计具有重要指导意义。Objective Terahertz(THz)waveguides are essential functional devices for the long-distance propagation and interconnection of THz waves;thus,they play an increasingly important role in THz applications,i.e.,in wireless communications,medical imaging,and security inspections.To achieve high transmission efficiency and integration,various THz waveguides using different guiding mechanisms have been developed,including dielectric,photonic crystal,anti-resonance,and surface plasmonic waveguides.Recently,graphene-based hybrid plasmonic THz waveguides have attracted significant attention because of their tunable and flexible transmission.However,the inherent optical properties of two-dimensional graphene,such as the low absorption of incident waves and weak electromagnetic response,pose challenges in the design of high-performance waveguides.Emerging three-dimensional Dirac semimetals(3D DSMs)have high carrier mobilities and tunable energy band characteristics comparable to those of graphene,while overcoming the above-mentioned inherent shortcomings of graphene.In this study,we propose a tunable broadband hybrid plasmonic THz waveguide based on a 3D DSM dielectric ridge structure.The transmission characteristics are systematically simulated using the finite element method,and the effects of the structural parameters and Fermi energy of the DSM are analyzed.Methods A THz waveguide structure is designed in this study based on a 3D DSM hybrid plasmonic mechanism,which comprises a DSM layer, SiO2 layer, and Si layer from top to bottom (Fig. 1). The corresponding thicknesses are optimized to be 4, 2, and10 μm, respectively. First, the complex permittivity of the 3D DSM at different Fermi levels in the THz regime is calculated based onthe Kubo formula and two-band model (Fig. 2). Finite element method-based simulations are performed to reveal the quantitativeinfluences of the structural geometric parameters and DSM Fermi energy on the THz transmission characteristics, including the realpart of the effective mode index, normal

关 键 词：太赫兹波导 狄拉克半金属 可调谐波导 宽带 混合等离激元 

分 类 号：TN814[电子电信—信息与通信工程]