Design Of 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 designing the dimensions and shape of the unit cell.it shows significant applications in electromagnetism,optics and materials science.Graphene stable in nature has been verified in 2004,which has attracted potential applications in many branches of engineering due to its unique properties of electric.Graphene-based metamaterial is an important subject of metamaterials owe to the ability of supporting surface plasmon polariton waves.In this paper,we focus on the theoretical research and design of graphene-based metamaterials terahertz absorber,the main contents are as follows:1.A novel broadband metamaterial terahertz absorber based on patterned graphene is designed and numerically studied.The proposed absorber has a typical three layered structure that consist of patterned graphene layer,instead of metasurface layer,dielectric spacer layer and ground plane layer.The total thickness of the proposed structure is 33.254?m.It should be emphasized that mechanism for the proposed broadband absorber obtained a 1.026-THz bandwidth with absorbance above 80%is the superposition of two absorption peeks,which result from surface plasmon resonance at f=1 THz,and the F-P oscillations at f= 1.35 THz.Further numerical calculations have demonstrated that the proposed absorber was polarization-independent and insensitive to the angle of the incident wave.2.A tunable metamaterial terahertz absorber based on the graphene square ring is proposed by using graphene square ring as top layer,silicon chunk as dielectric spacer,and A1 chip as ground plane layer.The absorption spectrum is shown that a near 100%perfect absorption is achieved at 0.294 THz and 0.876 THz stemming from the interaction between the multiple reflection inside the cavity,and 60%absorption is obtained at 1.458 THz deriving from the surface plasmon resonance.The proposed tunable absorber is insensitive to the polarization and the incident angle.The absorption and resonant frequency can be tunable through the change of chemical potential of graphene and the thickness of spacer.