Dynamically Tunable Resonant Strength in Electromagnetically Induced Transparency (EIT) Analogue by Hybrid Metal-Graphene Metamaterials

Chaode Lao,Faqiang Wang,Hongyun Meng,Hongzhan Liu,Yaoyao Liang,Xianjun Wang,Jianping Guo,Haihua Fan,Zhongchao Wei

doi:10.3390/nano9020171

Abstract

In this paper, a novel method to realize a dynamically tunable analogue of EIT for the resonance strength rather than the resonance frequency is proposed in the terahertz spectrum. The introduced method is composed of a metal EIT-like structure, in which a distinct EIT phenomenon resulting from the near field coupling between bright and dark mode resonators can be obtained, as well as an integrated monolayer graphene ribbon under the dark mode resonator that can continuously adjust the resonance strength of transparency peak by changing the Fermi level of the graphene. Comparing structures that need to be modulated individually for each unit cell of the metamaterials, the proposed modulation mechanism was convenient for achieving synchronous operations for all unit cells. This work demonstrates a new platform of modulating the EIT analogue and paves the way to design terahertz functional devices which meet the needs of optical networks and terahertz communications.

Highlights

EIT is a concept describing a sharp transmission window generated in a broad absorption profile, and was first discovered in the process of atomic system experiments [1,2,3]
Most EIT-analog metamaterials are composed of common noble metal materials with a fixed response frequency under fixed structural parameters where the dynamically adjustable function is usually realized by changing the structural parameters of the metamaterial, which is very inconvenient and impractical
An innovative method to realize dynamically tunable EIT for the resonance strength rather than the resonance frequency of the transmission windows is proposed at the terahertz spectrum

Summary

Introduction

EIT is a concept describing a sharp transmission window generated in a broad absorption profile, and was first discovered in the process of atomic system experiments [1,2,3]. Even though some methods have been put forward to dynamically modulate the analogues of EIT in metamaterials, such as changing the incident light angles [9,10] or tuning an external magnetic field [11], their modulation methods remain complicated and the modulation response speeds (MRS) are still very low.

Results

Conclusion