Magnetized Graphene-Based Metasurface for Terahertz Cross-Polarization Conversion

Abstract

A broadband magnetically tunable reflective metasurface based on magnetized graphene is presented for terahertz cross-polarization conversion. The metasurface adopts a three-layer stacked configuration consisting of a patterned graphene resonator, a dielectric spacer, and a metallic ground plane. Under perpendicular magnetic induction, magnetized graphene exhibits in-plane gyrotropic surface conductivity featuring prominent Hall components. Coupled with resonant interactions within the asymmetric unit cell, this intrinsic property facilitates the efficient conversion of normally incident y-polarized terahertz waves into x-polarized counterparts. Numerical results demonstrate that under an external magnetic induction of 3 T, the polarization conversion ratio exceeds 0.95 across the 1.40–2.80 THz band, generating a relative bandwidth of 66.7%. Moreover, its polarization conversion response can be dynamically modulated by varying the external magnetic induction. These simulated results verify that the designed metasurface is a promising candidate for gate-free, broadband, and reconfigurable terahertz polarization manipulation systems.