Graphene Absorption Enhancement Based On Surface Plasmons

Surface plasmons(Surface Plasmons,SPs)are electromagnetic oscillations formed by the interaction of incident photons and free electrons on the metal surface.It can not only realize the enhancement of the local field,but also break the diffraction limit of light.Most importantly,at the nanometer scale,plasmons can be used to control light.However,traditional metal-based surface plasmons have some drawbacks,such as the inability to achieve dynamic adjustment and high ohmic loss,which severely limits their development in the field of integrated photonics.Due to the excellent optical properties of graphene,As well as the dynamic adjustment of the Fermi level and the super-strong electromagnetic field localization,graphene-based surface plasmons have become a hot spot in recent years.In this paper,my main research work is to use the principle and properties of surface plasmons to design an absorber containing a graphene layer,and to achieve perfect absorption of a specific wavelength.Finally,we use the finite element method to carry out numerical simulation and Theoretical analysis,the main research work can be divided into the following parts:Chapter 1: Briefly introduced the basic principles and related properties of surface plasmons,and finally analyzed the current research status of graphene plasmons.Chapter 2: Mainly introduces the related theories of graphene,then based on the above theory,the graphene random phase approximation model is derived,and finally the numerical calculation method used in this article is introduced.Chapter 3: Designed and simulated a dynamically adjustable dual-band absorber.The simulation results show that the absorber has two nearly perfect resonance peaks at the wavelengths of 32.6 μm and 79.0 μm,respectively.Then,the physical mechanism of the absorption peak is obtained by the electric field distribution at the resonance wavelength,and the physical mechanism of the absorption peak is studied by controlling the variables.The geometric parameters of the absorber,the Fermi level of graphene,the relaxation time,and the effects of TE and TM polarized light incident at different incident angles on the resonance absorption peak.Chapter 4: Based on the absorber designed in the previous chapter,the two resonant absorption peaks cannot be adjusted separately.In the following research,in order to achieve the independent adjustment of the resonant absorption peak,we designed and simulated a double-layer The structure of graphene.The simulation results show that the absorber has three nearly perfect resonance absorption peaks at the wavelengths of 8.8μm,12.8μm,and 18.6μm,respectively.And it can also realize the independent dynamic adjustment of the three resonant absorption peaks,and the geometric parameters of the absorber,the Fermi level of the double-layer graphene,and the TE and TM polarized light incident at different incident angles are resonant through the controlled variables.The influence of the absorption peak.