Simulation of dynamically tunable and switchable electromagnetically induced transparency analogue based on metal-graphene hybrid metamaterial

A planar terahertz electromagnetically induced transparency-like (EIT-like) metamaterial, comprising an outer circular ring resonator (CRS) made by graphene, an inner vertical two-gap circular split ring resonator (VSRR) and a smaller horizontal two-gap circular split ring resonator (HSRR), is proposed. A distinct transparency window can be observed in two perpendicular polarization directions, respectively. By tuning the Fermi energy, the maximum modulation depths in two perpendicular polarization directions respectively can reach up to 83.54% and 94.39%. Meanwhile, the EIT-like effect, amplitude of transparency window, group delay and delay bandwidth product (DBP) can be adjusted dynamically without shift of frequency. The surface currents and three-level Lambda-type system can explain the physical mechanism of EIT-like effect. The analytical results based on a two-particle model are in good agreement with the numerical results. Our work provides a new method for dynamically adjustable terahertz slow light devices, which makes the graphene more controllable in metal-graphene hybrid structure. (C) 2019 Elsevier Ltd. All rights reserved.