Dynamically tunable plasmon-induced transparency in waveguide based on Dirac semimetal

¹ Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low- Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University Changsha 410082, China
² College of Physics and Electronics, Central South University - Changsha 410083, China
³ School of Physics and Optoelectronics, Xiangtan University - Xiangtan 411105, China

^(a) kele1110@hnu.edu.cn

Received: 23 November 2020
Accepted: 18 January 2021

Abstract

We report a numerical and theoretical study of the plasmon-induced transparency (PIT) effect in bulk Dirac semimetal (BDS) waveguide. This plasmon waveguide system is composed of a bus waveguide side coupled with two stub photoactive silicon resonators. The coupled mode theory (CMT) is introduced to analyze this system, and the theoretical results are perfectly consistent with the numerical calculation results. The numerical results show that the spectral characteristics of the structure depend on the coupling distance between the two stub photoactive silicon resonators. Intriguingly, the resonance characteristics of the transparent window can be actively controlled by adjusting the Fermi energy of the BDS or the intensity of the incident pump light. Finally, the group time delay of the PIT window can reach 3.7 ps, which is more suitable for applications with slow-light devices. Such a simple and multi-functional plasmon system is more conducive to the potential applications of composite high-performance devices.