提出了一种基于多孔硅的表面等离子共振传感模型: 棱镜-金属膜-多孔硅薄膜-待测介质。在该结构中, 多孔硅的折射率会随着样品浓度的变化而变化。利用有限元分析方法, 数值模拟得到该结构的共振光谱, 对模型进行了分析和参数优化。以乙二醇溶液为待测样本, 对提出的传感结构的传感性能进行分析, 得到该传感器对乙二醇的传感灵敏度约为267.85(°)/RIU, 约为Kretschmann棱镜结构灵敏度的2.13倍。

A prism surface plasmon resonance incentive model based on the porous silicon is proposed: prism base-metal-porous silicon layer-environmental media. The refractive index of the porous silicon will change with the sample absorbed on the porous silicon which causes the offset of surface plasmon resonance spectrum. Metal film and porous silicon layer compose the resonance film. According to the thin film optics and waveguide, the effect of resonance film on surface plasmons resonance spectrum is analyzed. With the method of finite element analysis, the resonance spectrum of the designed structure is obtained by numerical simulation. Through the comparison to the results, analysis and parameter optimization of the designed model are conducted. The results of analysis state the sensing performance of incentive model based on porous silicon is greatly improved compared by the common Kretschmann incentive model. The sensitivity of sensing structure is analyzed when the low concentration of ethylene glycol solution is as the sample. It can be obtained that the sensitivity is about 267.85(°)/RIU. That is about 2.13 times more than the sensitivity of the common Kretschmann incentive model. The resonance sensing of the designed structure provides theoretical reference for sample concentration detection, biological sensing and other aspects.