Dynamically Tunable of Terahertz Waves Based on Graphene Metasurface

A dynamically tunable metasurface based on graphene is proposed in this paper, which consists of split-ring resonator and graphene nanoribbon array. The simulated results show that not only the proposed structure could achieve the transmission with 87 %, but also the reflectivity of 25 % within a certain frequency range from 0.57 THz to 0.63 THz, meanwhile, which also can achieve 20 degrees reflection phase modulation. By changing the chemical potential (Fermi energy) of the graphene strips, the amplitude and phase of terahertz wave can be dynamically controlled. This designed graphene metasurface structure will be applied to control the mode competition in the terahertz gyrotron through manipulating the reflection wave, which is one of the most important factor influencing the mode competition.