Active Control of the THz Wave Polarization State by an Electronically Controlled Graphene Composite Metasurface

Active control of terahertz (THz) wave polarization state is great significance for sensitive detection, imaging and communication. Here, a tunable THz quarter plate designed by electronically controlling composite metasurface consisting the gold cross antennas monolayer graphene. The graphene acts as quarter-wave when chemical potential 0 eV, which incident converted from linear to circular polarization. After increased gradually, 0.5 transmitted changed right elliptical polarization, Furthermore, able be left if device clockwise rotated 90°. Therefore, could actively controlled proposed plate. Our work will offer new avenue modulation devices.