Research On Optical Transmission Properties In Two-dimensional Materials/dielectric Periodic Stacking Structure

Hyperbolic metamaterials are anisotropic and uniaxial artificial engineered subwavelength electromagnetic materials whose isofrequency contour is an open hyperboloid.It also has many unique features such as support for the propagation of large wave vectors,lithography-free ease of fabrication,and broadband non-resonant response.Because of these characteristics,it has important research and application value in many research directions such as negative refraction,subwavelength imaging,spontaneous radiation,heat transfer,and slow light effects.In recent years,with the discovery of their extraordinary physical,chemical and mechanical properties,two-dimensional materials have gradually become a research hotspot,and the research based on two-dimensional materials has been rapidly developed in many research fields.Among them,hyperbolic metamaterials based on two-dimensional materials have also been proposed and have attracted the attention of researchers.Up to now,some related research work has been reported,such as hyperlens,enhanced absorption,negative refraction,and thermal radiation.Based on various simulation and calculation methods such as finite element method and effective medium theory,the optical transmission characteristics of hyperbolic metamaterials composed of two-dimensional material/medium periodic multilayer structure are studied under three scenarios: light passing through a slit,light excited by an electric dipole,and light from the side.First of all,a multilayer structure based on the alternating graphene/silicon dioxide is proposed to realize a tunable dark hollow beam.The top layer of the structure is a silver layer with a hole.By changing the Fermi level,the effective permittivity of the multilayer structure satisfies the different signs of the in-plane component and the out-of-plane component and the multilayer structure shows hyperbolic dispersion.When a transverse magnetic wave is incident,the light will split into two subwavelength beams after it propagates through the slit.And a dark hollow beam can be achieved for circularly polarized incidence.The diameter of the dark hollow can also be flexibly adjusted by changing the Fermi level of graphene.Later,based on the photon spin Hall effect,alternating graphene/silicon dioxide multilayer structure is used to realize dynamically tunable directional subwavelength beam propagation.A dipole emitter which placed at the boundary of multilayer structure excites light of different polarizations,which correspond to different propagation modes in the multilayer structure.In particular,when the dipole excites right-handed circularly polarized light,the right channel is open and the left channel is closed.And when the dipole excites left-handed circularly polarized light,the left channel is open and the right channel is closed.Thus,the subwavelength beam with ?/40 full-with half maximum can be excited and propagates along the left or right channel,which is dependent on polarization handedness.The results can be well explained by the theory of near-field interference.In addition,the unidirectional propagation angle of light can be adjusted by changing the external electric field bias applied to graphene.Finally,alternating graphene/silicon dioxide and alternating black phosphorus/silicon dioxide multilayer structure are proposed to realize an ultra-narrow angular optical transparency window based on photonic topological transition,respectively.For the graphene multilayer structure,the dispersion of the multilayer structure can be adjusted from elliptical dispersion to hyperbolic dispersion by changing the Fermi level of graphene.Based on in-plane anisotropy of black phosphorus,the black phosphorus multilayer structure's iso-frequency contour can transit from open hyperboloid to closed ellipsoid by changing the angle of the incidence plane.The results obtained by finite element method and transfer matrix method both demonstrate that a narrow angular optical transparency window can be achieved at photonic topological transition point.And the angle half-maximum and full-width of the optical transparency window is approximately 0.8° and 1.32°.By changing the thickness of silicon dioxide,the electron doping of black phosphorus,and the Fermi level of graphene,the photonic topological transition point can also be adjusted.