Broadband tunable perfect absorber using terahertz graphene metasurface

Abstract

Since the discovery of graphene, it has attracted considerable attention in the field of basic research and industry. Graphene has a unique band structure with a junction between the valence band and the conduction band at the six corners of the Brillouin zone. In the vicinity of this so-called Dirac point, energy dispersion is linear and produces unique optical and electronic properties. The electrons behave like relativistic massless particles and can be described by a Dirac-like equation. Especially, it has attracted much attention as a new active material like as liquid crystal due to its ability to freely control Fermi energy by injecting electrons or holes. In particular, in the field of metamaterials,many studies have been conducted to control the optical characteristics combined with graphene. However, it does not overcome the limitations of the narrow-band behavior of the metamaterials, and graphene was applied as a means of changing the optical properties. In this thesis, I will explore how to fabricate an broadband absorber that completely absorbs terahertz waves by varying the surface conductivity of graphene.