A waveguide coupled surface plasmon sensor for detection of liquid with high refractive index (RI) is designed based on polymer materials. The effects of variation of the thickness of the Au film, polymethyl methacrylate (PMMA) buffer, and waveguide layer on the sensing performance of the waveguide are comprehensively investigated by using the finite difference method. Numerical simulations show that a thinner gold film gives rise to a more sensitive structure, while the variation of the thickness of the PMMA buffer and waveguide layer has a little effect on the sensitivity. For liquid with high RI, the sensitivity of the sensor increases significantly. When RI of liquid to be measured increases from 1.45 to 1.52, the sensitivity is as high as 4518.14nm/RIU, and a high figure of merit of 114.07 is obtained. The waveguide coupled surface plasmon RI sensor shows potential applications in the fields of environment, industry, and agriculture sensing with the merits of compact size, low cost, and high integration density.

基于聚合物材料设计了一种波导耦合表面等离子体激元传感器，用于检测高折射率（RI）的液体。利用有限差分法，综合研究了金膜厚度，聚甲基丙烯酸甲酯（PMMA）缓冲层和波导层厚度的变化对波导传感性能的影响。数值模拟表明，较薄的金膜会产生更敏感的结构，而PMMA缓冲层和波导层厚度的变化对灵敏度的影响很小。对于高RI的液体，传感器的灵敏度会大大提高。当待测液体的RI从1.45增加到1.52时，灵敏度高达4518.14nm / RIU，并获得114.07的高品质因数。