In this paper, a novel multifunctional four-layer SPR structure (prism-metal- electro-optic crystal- external layer) is proposed which can not only measure the RI of external layer, but can also realize accurate measurement of the applied electric fields by fixing the external layer. When the structure is used for measuring the RI of external analytes, the metal and electro-optic crystal layers were optimized by FDTD solutions software. The thickness of Ag layer is 50 nm, and the optimum electro-optic crystal is BaTiO₃ with a thickness of 15nm. The detection range is 1.33–1.37 and the sensitivity is up to 5602 nm/RIU. When the structure is used to measure electric field, simulation results shows an excellent linear relationship between the RI of the electro-optic crystal layer and the resonance wavelength, which is different from traditional SPR sensors. This special phenomenon greatly reduces the measurement error and improves measurement accuracy, for example a spectrometer with resolution of 1pm can achieve the minimum measurement of $7.729\times {10}^{-2}\text{V}$ voltage.

本文提出了一种新颖的多功能四层SPR结构（棱镜-金属-电光晶体-外层），它不仅可以测量外层的RI，还可以通过以下方式实现对施加电场的精确测量：固定外层。当该结构用于测量外部分析物的RI时，通过FDTD解决方案软件优化了金属和电光晶体层。Ag层的厚度为50 nm，最佳电光晶体为BaTiO ₃厚度为15nm。检测范围为1.33–1.37，灵敏度最高为5602 nm / RIU。当使用该结构测量电场时，仿真结果显示出电光晶体层的RI与谐振波长之间的线性关系极佳，这与传统的SPR传感器不同。这种特殊现象大大降低了测量误差并提高了测量精度，例如，分辨率为1pm的光谱仪可以实现$7.729\times {10}^{--2}\text{V}$ 电压。