Research On Metamaterial Terahertz Absorber Based On Graphene

Metamaterial is a kind of artificial composite material with periodic unit cell structure,which has exotic properties of electromagnetic caused by appropriately designing the geometry and lattice structure of the unit cell.It shows significant applications in electromagnetism,optics and materials science.The terahertz waves have many special physical properties compared with other bands and therefor have great research significance.The research of terahertz-related functional devices can promote the development of THz technology.In this paper,the absorber is set as the research object.There are two kinds of metamaterial absorber based on graphene are proposed and numerically studied.The main contents are as follows:1、An ultra-thin narrow-band terahertz absorber based on graphene open loop is designed.The top layer of the structure is the graphene open loop,the dielectric layer is silica and the bottom layer is the gold plane.The numerical calculations have demonstrated that the proposed absorber structure has a distinct resonance peak at 8.55 THz with absorbance above 98%.The different parameters of the structure are calculated in order to analyze the influence on the absorbance.2、A tunable broadband terahertz absorber based on multi-layers graphene films is proposed.This structure is different from the typical three-layer metamaterial absorber.Here,two layers of graphene plane are sandwiched in the dielectric layer.The simulation result indicated that the graphene plane in the dielectric layer plays an important role in the broadband absorption.The absorption can be tunable through the change of chemical potential of graphene.3、The influence of the Fermi level of graphene on the absorption in the broadband absorber is analyzed.The absorption characteristics of the absorber were analyzed by talking about the current density distribution of graphene.The proposed tunable absorber is insensitive to the polarization and the incident angle.