We propose a surface plasmon resonance (SPR) sensor based on phase modulation and polarization interferometry, both of which provide a refractive index (RI) resolution of the same order as that of SPR sensors of the phase type. And it has a wide dynamic range and insensitivity of RI resolution to the thickness of metal films as that of the intensity type SPR sensors. In this letter, we choose electro-optic (EO) phase modulation instead of the angle modulation. We demonstrate theoretically that with the EO phase modulation, our sensor could provide a better RI resolution.

表面等离子体共振(SPR)传感技术具有很高的折射率分辨率。但是其折射率分辨率对金属膜厚度非常敏感，影响了SPR传感器的适用性。使用一种叫做“偏振干涉”的技术，来减小光谱型SPR传感器的折射率对金膜厚度的敏感性。实验结果表面，偏振干涉能够降低SPR光谱的最小值，提高使用非最佳金属膜的SPR传感器的折射率分辨率。金膜厚度在28.16~54.38 nm范围内变化时，系统的折射率分辨率达到3.9×10-7~8.1×10-7RIU(折射率单位)。