Terahertz wave transmission modulation based on graphene metasurface

Graphene, as a special material with a thickness of only 0.34 nm, has many outstanding properties that are difficult to achieve with ordinary materials, so it is often regarded as an indispensable core material for active regulatory devices in the terahertz band. In this article, the authors design a terahertz wave device based on graphene. The metasurface consists of PET, a monolayer of graphene attached to PET, an ion-gel, and an asymmetrical four cross-shaped metal elements. The results show that the extraordinary optical transmission (EOT) characteristics of terahertz waves can be realized by introducing four asymmetrical cross-shaped metal subunits into the subwavelength metal aperture. In addition, the transmittance of the periodic structure can be reduced from 86.6% to 53.9% by increasing the graphene Fermi energy, and the modulation amplitude can reach 32.7%. The proposed graphene-based active terahertz transmission modulation metasurface is expected to have certain application value in the fields of electromagnetics and optical active modulation.