基于波矢可调谐对称结构的条波导型SPR传感系统研究

针对目前波导型SPR传感器波矢匹配条件受限及较难与光纤实现固化对接进而实现在线传感的缺点，研究由条波导激励对称结构的SPR传感系统。通过对由金属——介质——金属构成的对称结构进行模式分析，研究可在该结构内激发SPW的可能性及其波矢可调谐机制。实验制备单模条波导并激励对称传感结构，对比了条波导激励传统结构与对称结构的检测折射率范围，研究了对称结构中金属材质，金属膜厚及介质厚度对测量结果的影响，给出了折射率测量的结果，实验证明，采用对称结构实现传感，可通过镀金属膜的厚度来改善传感特性，调节两金属膜之间介质的厚度可以实现波矢匹配的调节，进而使得被测范围具有一定的可调性，具有较好的线性。

Study on the SPR sensing system based on the adjustable wave vector symmetrical structure

The wave vector matching condition is limited in the waveguide SPR sensor because of the large value of the mode refractive index. Most of the waveguide SPR sensors are excited by the planar waveguide,so it is difficult to docking with fiber. A symmetrical SPR sensing structure excited by the channel waveguide is presented in this pa?per to overcome those difficulties. By analyzing the mode characteristic of the metal-dielectric-metal structure,the possibility of the SPW excitation in this structure and the adjustablemechanism of the wave vector are studied. The single-mode channel waveguide is prepared and used to excite the symmetrical sensing structure. The testing range of symmetrical structure and traditional structure excited by the channel waveguide are compared. Effects of metal ’ s thickness,the thickness on the measurement results are researched. Experimental results show that the sensing characters can be changed by the thickness of the metal films,andthe wave vector matching condition can be adjust?ed by changing of dielectric’s thickness between the two metal films,thus the testing range is adjustable. Testing re?sults have good linearity.