内置调制层型光纤表面等离子体波共振传感器研究

研究了一种基于内置调制层结构的光纤表面等离子体波共振(SPR)传感器。通过在金膜与纤芯的内侧增覆具有不同厚度和属性的光学透明薄膜作为内调制层,构成了性能独特的光电复合薄膜,起到调节倏逝波矢量和金膜表面等离子体振荡波矢量的双重作用,进而控制共振效应,为调节灵敏度提供依据。采用时域有限差分方法对内置调制层结构光纤SPR共振激励模型属性进行数值仿真。在此基础上,研制了用于液体折射率测量的内置调制层型光纤SPR传感探针。实验结果表明,该传感器在1.335～1.392折射率范围内,随着待测液体折射率的增大,SPR共振光谱向长波方向偏移,且灵敏度达到2263.1nm/RIU,与基于纤芯-金膜-环境介质三层结构的常规光纤SPR传感器相比提高一倍,能够更好地满足环境折射率检测的需求。

Research of Optical Fiber Surface Plasmon Wave Resonance Sensor Based on Built-in Modulation Layer

An optical surface plasma wave resonance (SPR) sensor based on the built-in modulation layer structure is studied. A kind of photoelectric composite film with unique performance is constituted by coating optical transparent films with different thicknesses and properties between the gold film and the fiber core, as internal modulation layer. It can adjust both the evanescent wave vector and gold film surface plasma oscillation wave vector, and then control resonance effect to provide a basis for sensitivity adjustment. Numerical simulation is done on the attribute of built-in modulation layer structure optical fiber SPR resonance incentive model using the finite difference time domain method. On this basis, a built-in modulation layer type optical fiber SPR sensor probe is developed for liquid refractive index measurement. The experiment results show that as the refractive index increases, the SPR resonance spectrum shifts to the long wave direction, in refractive index range from 1.335 to 1.392. The sensitivity can reach to 2263.1 nm/RIU, which is two times of conventional optical fiber SPR sensor based on the fiber core-gold film-environment medium three layer structure. All show that this new sensor can meet the needs of the environment index test much better.