No abstract

The photonic spin Hall effect (PSHE), characterized by two splitting beams with opposite spins, has great potential for applications in nano-photonic devices, optical sensing fields, and precision metrology. In this contribution, we presented the significant enhancement of terahertz (THz) PSHE by taking advantage of the optical Tamm state (OTS) in InSb-distributed Bragg reflector (DBR) structure. The spin shift of reflected light can be dynamically tuned by the structural parameters (e.g. the thickness) of InSb-DBR structure as well as the temperature, and the maximum spin shift for a horizontally polarized incident beam at 1.1 THz can reach up to 11.15 mm. Moreover, we proposed a THz gas sensing device based on the enhanced PSHE via the strong excitation of OTS for InSb-DBR structure with a superior intensity sensitivity of 5.873×104 mm/RIU and good stability. This sensor exhibits two orders of magnitude improvement compared with the similar PSHE sensor based on InSb-supported THz long-range surface plasmon resonance. These finds may provide an alternative way for the enhanced PSHE and offer the opportunity for developing new optical sensing devices.