Spin Hall Effect Of Graphene/Hexagonal Boron Nitride Hyperbolic Metamaterials

Hexagonal boron nitride(h BN),as a natural hyperbolic material,has better optical response and lower optical loss than metal or synthetic hyperbolic metamaterials.Graphene is composed of two-dimensional single-layer carbon atoms arranged in a hexagonal honeycomb lattice.Due to its special electronic energy band structure,graphene plasmons exhibit unique electrical possibilities.Excellent performance such as tonality,low intrinsic loss and high light field localization.In this paper,the photonic spin Hall effect generated on the surface of graphene/h BN heterostructure and graphene/h BN superlattice structure formed by coupling hexagonal boron nitride and graphene is deeply discussed by classical electromagnetic theory and angular spectrum theory,the main research contents are as follows:1.A tunable photonic spin Hall effect structure is constructed by introducing a layer of graphene on top of hexagonal boron nitride.Interaction of phonon polarons(SPh Ps)in h BN with plasmonic polarons(SPPPs)in graphene generates hybrid polarons,leading to complex photonics in graphene/h BN heterostructures Spin Hall Effect(SHEL).We are focus on the generated SHEL near the two remaining frequency bands of h BN,especially the frequency region near the near-zero point(ENZ).It is found that in the vicinity of ENZ in the first residual frequency band,SHEL is significantly enhanced in a wide range of incident angles,while in the second residual frequency band,SHEL is significantly weakened,and even tends to zero under a certain condition.According to the dispersion properties of the system,it can be seen that the enhanced SHEL near the ENZ of the first residual frequency band is mainly attributed to the generation of surface plasmon phonon polarons(SPPPs),while the weakened SHEL located in the second residual frequency band SHEL mainly originates from the excitation of hyperbolic plasmonic phonon polarons(HPPPs).When the ratio and phase difference of the Fresnel reflection coefficients of the s-wave and p-wave meet certain conditions,the spin shift can reach an extreme value and can be effectively adjusted by adjusting the chemical potential.In addition,the influence of the tilt angle of the optical axis,the thickness of hexagonal boron nitride and the incident angle on the spin Hall effect is also discussed.These findings may provide potential applications for spin optics and photonic control-based nano-optics.2.Based on the single-layer thin film structure,a graphene/h BN superlattice structure was designed.Using the transfer matrix method,the spin Hall effect generated by the reflected beam on the surface of the medium is further explored.The study found that when the material structure is changed to a superlattice structure,the existence of spin shifts can be observed in a wider frequency range by adjusting the chemical potential.When the incident angle is near the Brewster angle and the phase satisfies certain conditions,the extreme value of the spin shift of the system can be obtained.In addition,the magnitude of the spin shift and the frequency position corresponding to the spin shift can be effectively regulated by adjusting the incident angle and the tilt angle of the optical axis.