Enhanced and tunable terahertz spin hall effect of reflected light due to tamm plasmons with topological insulators

In this paper, the enhanced photonic spin hall effect (PSHE) of reflected light at terahertz (THz) frequencies is achieved by using a multilayer structure consisting of Bi2Se3, spacer layer, and distributed Bragg reflector structure. This enhanced spin hall effect (SHE) phenomenon originates from the excitation of optical Tamm states (OTSs) at the interface between the Bi2Se3 and distributed Bragg reflector structure. It is found that the PSHE of the reflected light can be flexibly controlled by properly varying the Fermi energy of the topological insulators. Moreover, the spin behavior of the composite structure is also proved sensitive to incidence angle and the dispersion characteristics of the spacer layer, thus making this configuration an effective candidate for developing photonic devices based on photonic PSHE at the terahertz range.