Hybrid magnetic plasmon resonance induced tunable half-wave plate based on graphene-dielectric-metal structure

Abstract

We propose a terahertz half-wave plate composed of a periodic array of rectangular-shaped metal-dielectric-graphene (RMDG) sandwich structure on a dielectric substrate supported by a thick metallic film. The role of graphene sheet is to combine with the rectangular-shaped metal to provide tunable anisotropic hybrid magnetic plasmon resonance. The results reveal that about 90% of energy of the incident linearly polarized light at a certain frequency is converted to the perpendicular polarization direction after reflection from the wave plate. The high energy polarization conversion efficiency is attributable to the fact that the electric vector of the hybrid magnetic plasmon resonance in RMDG is mainly perpendicular to the graphene sheet and the absorption loss of graphene is suppressed. The half-wave plate we demonstrate here, consisting of nanostructured metal and non-structured graphene, utilizes mature metal nanostructure preparation process and avoids the graphene processing, which consequently facilitates the fabrication and promotes the application of half-wave plate.