Active graphene plasmonic grating for terahertz beam scanning device

We have proposed an electrically controllable terahertz (THz) beam scanning device based on asymmetric graphene plasmonic grating. It is proved that the dispersion relation of surface plasmon waves can be efficiently manipulated on the periodic metal-dielectric-graphene plasmonic structure by an external bias voltage, and thus the derivation angle of the THz beam can be actively tuned. The numerical results show that the radiation angle of THz waves through this device can be tuned from −18° to 18° with the bias changing from 53.5 mV into 368.8 mV at the operating frequency of 0.5 THz. This electrically active beam scanning device has important application in the THz imaging, radar and communication systems.