Dynamic focusing of linearly polarized terahertz waves with graphene-loaded metasurface

Reconfigurable metalenses have received a significant amount of attention in recent years due to its versatility. In this paper, a reconfigurable graphene-integrated plasmonic metalens operating as a converging lens for linearly polarized terahertz (THz) plan waves is proposed and numerically investigated at 0.83 THz. The beam focusing is realized by the geometrical configuration of C-shaped ring resonators. Furthermore, focal tuning is realized by gate-controlled graphene, which locally changes the permittivity in response to external biasing. This design provides a simple route to electrically tunable optical and optoelectronic devices.