Active manipulation of electromagnetically induced transparency in a terahertz hybrid metamaterial

The metamaterial analogue of electromagnetically induced transparency (EIT) in terahertz (THz) regime holds fascinating prospects for filling the THz gap in various functional devices. In this paper, we propose a novel hybrid metamaterial to actively manipulate the resonance strength of EIT effect. By integrating a monolayer graphene into a THz metal metamaterial consisting of a split ring resonator (SRR) enclosed within a larger closed ring resonator (CRR), an on-to-off modulation of the EIT transparency window is achieved under different Fermi levels of graphene. According to the classical two-particle model and the distributions of the electric field and surface charge density, the physical mechanism is attributed to the recombination effect of conductive graphene. This work reveals the universal interaction of the monolayer graphene on the SRR and offers a new perspective towards designing THz functional devices.