Enhancing terahertz photonic spin Hall effect via optical Tamm state and the sensing application |
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Institution: | 1.School of Science, New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210023, China;2.College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, China;3.School of Electrical Engineering, Nanjing Vocational University of Industry Technology, Nanjing 210023, China |
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Abstract: | The photonic spin Hall effect (PSHE), characterized by two splitting beams with opposite spins, has great potential applications in nano-photonic devices, optical sensing fields, and precision metrology. We present 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 the 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 propose a THz gas sensing device based on the enhanced PSHE via the strong excitation of OTS for the 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 findings may provide an alternative way for the enhanced PSHE and offer the opportunity for developing new optical sensing devices. |
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Keywords: | photonic spin Hall effect optical Tamm state InSb gas sensor |
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