Highly sensitive refractive index sensor based on the lossy mode resonance enhanced photonic spin Hall effect

Abstract

Different from surface plasmon resonance (SPR) that only can be excited by p -polarized light, lossy mode resonance (LMR) can be achieved with both p - and s -polarized light, thus providing a pathway for enhanced transverse spin-dependent shift (SDS) of the photonic spin Hall effect (PSHE) for the horizontal and vertical polarization states. The maximum transverse SDSs of 13.28 µm and 7.64 µm for the horizontal and vertical polarization states are achieved, respectively, which are about 12 and 7 times the wavelength of incident light. A refractive index sensor based on the LMR enhanced PSHE is proposed, and the maximum refractive index sensitivity of 13500 µm/RIU (RIU, refractive index unit) can be obtained. Our investigation provides an alternative method for the enhancement of PSHE, thus opening up opportunities for the design of various photonic devices based on PSHE.