High sensitivity gas sensor based on surface exciton polariton enhanced photonic spin Hall effect

In this paper, the sub-wavelength transverse displacement of photonic spin Hall effect (PSHE) is significantly enhanced by the surface exciton polariton (SEP) for application in gas sensing. The transverse displacement of 14.4 times the wavelength of incident light is achieved with the SEP enhanced PSHE, which is about 3 times that of surface plasmon resonance enhanced PSHE. A gas sensor based on SEP enhanced PSHE is proposed for the detection of SO₂, and the refractive index sensitivity of 6320.4 µm/RIU is obtained in the refractive index range from 1.00027281 to 1.00095981. These results undoubtedly demonstrate SEP to be a promising mechanism for PSHE enhancement, and open up new opportunities for highly sensitive gas sensing, biosensing, and chemical sensing.