基于对称平板波导型SPR液体折射率传感特性

Characteristics of liquid refractive index sensing based on symmetric planar waveguide SPR

表面等离子体共振(SPR)技术在外界环境折射率测量上有着广泛应用。设计了一种对称平板波导结构,利用时域有限差分法对波导结构中SPR效应与外界环境折射率的关系进行数值模拟,对金属材料选择以及传感区域长度进行了优化,并研究了不同阶次的模式对传感器灵敏度的影响。仿真结果表明:当外界环境折射率为1.38时,相较于基模条件下4100 nm/RIU的灵敏度,三阶模传感器的灵敏度提高到6209 nm/RIU,最大灵敏度提高了51%;当外界环境折射率为1.34~1.38时,传感器平均灵敏度从2900 nm/RIU提高到4025 nm/RIU。

Surface plasmon resonance(SPR)technology has been widely used in refractive index measurement in the external environment.In this paper,a symmetrical planar waveguide structure is designed.The relationship between SPR effect and the refractive index of the external environment is numerically simulated by using the finite difference time domain method.The selection of metal materials and the length of sensing area are optimized.The effects of modes of different orders on the sensitivity of the sensor are studied.The simulation results show that when the refractive index of the external environment is 1.38,compared with the sensitivity of 4100 nm/RIU under the base mode condition,the sensitivity of the third-order mode sensor is increased to 6209 nm/RIU,and the maximum sensitivity is increased by 51%.When the ambient refractive index is 1.34-1.38,the average sensor sensitivity increases from 2900 nm/RIU to 4025 nm/RIU.