Graphene Tamm plasmon-induced enhanced and tunable photonic spin hall effect of reflected light in terahertz band

Abstract

In order to enhance the photonic spin hall effect (PSHE) of the reflected light at terahertz frequencies, we propose a multilayer structure where the one-dimensional photonic crystal (1D PC) is coated with a piece of monolayer graphene separated by a spacer layer. Enhanced photonic spin hall effects are obtained by this structure based on the excitation of optical Tamm states (OTSs) on the interface between the monolayer graphene and 1D PC. According to the analytical results, the PSHE of the reflected light can be flexibly controlled by properly varying the Fermi energy and relaxation time of graphene. It is also proved that the spin behavior of the composite structure has a great sensitivity to the incidence angle and the dispersion characteristics of the spacer layer, thus making the proposed structure a competitive candidate for designs of new photonic devices on the basis of photonic SHE at terahertz band.