Tunable Unidirectional Light Transmission In A Graphene-Metal Hybrid Metamaterial

Graphene's unique properties, such as strong plasmonic response and electrostatic doping, enable control over the properties of light in an active way. In this paper, we propose a graphene-metal hybrid metamaterial, which exhibits tunable wideband unidirectional light transmission. The hybrid metamaterial consists of a complementary split-ring graphene and a metallic grating. Unidirectional optical transmission with a wide bandwidth of 14.8% of the central frequency at 29.3THz and a large tuning range of 6.6THz is found to be achievable in simulations. The light reflection and graphene absorption are shown to be the major factors limiting the efficiency of unidirectional transmission. A large electron scattering time of graphene is beneficial for improving the transmission efficiency. The graphene-metal hybrid metamaterial enables active control over the propagation of light, which could be of interest for infrared isolation, polarization transformation, etc.