Enhanced spin hall effect of reflected light due to Optical Tamm states with Dirac semimetal at the terahertz range

Abstract: The enhanced photonic spin hall effect (PSHE) plays a positive role in the flexible manipulation of photons. Here, by combining Dirac semimetals with Bragg reflector constructed by one-dimensional photonic crystal, we theoretically design a simple multilayer structure to enhance and manipulate the PSHE. Through the detailed and optimal design of the conductivity characteristics of Dirac semimetals and the structural parameters of the whole model, we realize the excitation of Optical Tamm states (OTSs) in the multilayer structure, so that the PSHE can be enhanced and controllable. The theoretical results show that by optimizing the Fermi energy and the thickness of Dirac semimetal, the reflection coefficient ratio can be increased under p-polarization and s-polarization, thus creating conditions for enhanced PSHE. In addition, the effects of the incident angle and the parameters of the spacer layer on the PSHE are also clarified. We believe above results can provide a new paradigm for the construction of controllable spin devices.