Dynamically tunable polarization beam splitting with slotted graphene patch arrays in the terahertz regime

Abstract

Inspired by the reflectarray concept, we propose a polarization beam splitter (PBS) using orthogonally oriented slotted graphene patches configured in a two-layer metasurface, which bidirectionally deflects the incident wave depending on its polarization in the terahertz (THz) regime. Our device employs slotted graphene patch resonators as plasmonic dipoles to provide a nearly 360° phase shift for orthogonal linearly polarized waves, which can be independently controlled for each polarization. The PBS operating frequency is also continuously tunable over a 20% frequency bandwidth, just by equally varying the graphene patches’ Fermi level in the device structure. In light of highly confined electromagnetic fields for slotted graphene patches, they have a very small effective mode volume, enabling us to utilize miniaturized metasurfaces and components. Moreover, due to the pattern simplicity of the slotted graphene patches, they can be used as practical building blocks for other THz metasurfaces with novel functionalities, which can be likely avenues for future telecommunication applications.