Narrow and Dual-Band Tunable Absorption of a Composite Structure with a Graphene Metasurface**Supported by the Program for the University Excellent Young Talents under Grant No gxyq2017074, the Anhui Key Research and Development Plan under Grant No 1704e1002208, and the Natural Science Research Project of Anhui Province Education Department under Grant No KJ2017A396.

Abstract

A tunable absorber, composed of a graphene ribbon on two layers of TiO2-Au between two slabs of dielectric material all on a metal substrate, is designed and numerically investigated. The absorption of the composite structure varies with the geometrical parameters of the structure and the physical parameters of graphene at mid-infrared frequencies. The numerical simulation shows that a near-perfect absorption with single and dual bands can be achieved in a certain frequency range. We also analyze the electric and surface current distributions to study the dual-band absorber. The results show that the absorber can be tuned by the chemical potential and electron–phonon relaxation time of graphene, and electromagnetically induced transparency phenomenon can be obtained. The results of this study may be beneficial in the fields of infrared communication, perfect absorbers, sensors and filters.