Research On The Absorption Characteristics Of Terahertz Wave Based On Electromagnetically Induced Absorption Analog

Metamaterials have been widely used in the microwave and terahertz fields because of their unique physical phenomena,such as negative permeability,negative permittivity and electromagnetically induced transparency,can be obtained by designing the structure of metamaterials.In this thesis,the absorption characteristics of electromagnetically induced absorption analog in terahertz band are studied,including transmission-type electromagnetically induced absorption modulator and reflection-type perfect absorber.The main research contents of this article are as follows:(1)The basic principles of electromagnetically induced absorption and the Lorentz coupling theoretical model based on metamaterials were analyzed.In addition,the surface conductivity model of graphene was explored,which provided a theoretical basis for subsequent analysis.(2)A double-layer terahertz metamaterial structure was studied to realize electromagnetically induced absorption analog phenomenon and explored the effects of absorption modulation under different structure sizes.In addition,the combination of metamaterials and graphene achieved dynamic modulation of the absorption spectrum.The modulation effect at different Fermi levels of graphene was studied and a modulation degree of 49% was obtained.(3)The physical mechanism for perfect absorption of the reflective terahertz double-layer metamaterial structure was studied,and the absorption rate reached 99.9%.By changing the thickness of the dielectric layer and the structure size,the frequency shift of the absorption peak can be obtained to different degrees.