Broadband Filter and Adjustable Extinction Ratio Modulator Based on Metal-Graphene Hybrid Metamaterials.

Haoying Sun,Lin Zhao,Zhongchao Wei,Jianping Guo,Hongyun Meng,Hongzhan Liu,Jinsong Dai,Qiaofeng Dai,Yaoyao Liang

doi:10.3390/nano10071359

Haoying Sun, Lin Zhao + Show 7 more

Open Access

https://doi.org/10.3390/nano10071359

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Abstract

A novel multifunctional device based on a hybrid metal–graphene Electromagnetically induced transparency (EIT) metamaterial at the terahertz band is proposed. It is composed of a parallel cut wire pair (PCWP) that serves as a dark mode resonator, a vertical cut wire pair (VCWP) that serves as a bright mode resonator and a graphene ribbon that serves as a modulator. An ultra-broadband transmission window with 1.23 THz bandwidth can be obtained. The spectral extinction ratio can be tuned from 26% to 98% by changing the Fermi level of the graphene. Compared with previous work, our work has superior performance in the adjustable bandwidth of the transmission window without changing the structure of the dark and bright mode resonators, and has a high extinction ratio and dynamic adjustability. Besides, we present the specific application of the device in filters and optical modules. Therefore, we believe that such a metamaterial structure provides a new way to actively control EIT-like, which has promising applications in broadband optical filters and photoelectric intensity modulators in terahertz communications.

Highlights

Metamaterials that serve as kinds of artificial materials have received tremendous concern in modern materials science and physics [1,2] for their extraordinary material properties and flexible control of electromagnetic waves
Induced transparency (EIT) is a significant phenomenon which comes from the destructive interference between different excitation pathways in a three-level atomic system [12,13]
We proposed a hybrid metal–graphene metamaterial in the terahertz spectrum for the realization of changing the Electromagnetically induced transparency (EIT)-like transmission window and adjusting the spectral extinction ratio

Summary

Introduction

Metamaterials that serve as kinds of artificial materials have received tremendous concern in modern materials science and physics [1,2] for their extraordinary material properties and flexible control of electromagnetic waves. Induced transparency (EIT) is a significant phenomenon which comes from the destructive interference between different excitation pathways in a three-level atomic system [12,13] It can be potentially useful in many applications, such as the dynamic storage of light [14], slow-light devices [15], and nonlinear effects [16]. Our group proposed an active modulation of the amplitude of the EIT-like transmission window in terahertz-band metamaterials by changing the Fermi level EF of graphene [24]. The realization of broadening the transmission window and adjusting the spectral extinction ratio was done by manipulating the graphene instead of changing the structure of the dark and bright mode resonators We believe that such EIT metamaterials have promising applications in broadband slow-light devices, filters, and modulators in terahertz communications

Materials and Methods

Graphene-Based Tunable Metamaterial Electro-Optic Modulator

Prospects for Future Work