长周期光纤光栅表面等离子体共振增强传感器

Long Period Fiber Grating Surface Plasmon Resonance Enhanced Sensor

针对光纤表面等离子体共振传感普遍存在强度脆弱、灵敏度偏低及等离子体激发效率低下的问题,文章将长周期光纤光栅作为辅助平台,研究了表面等离子体共振传感器增强灵敏度的途径。在光纤光栅表面传感区域热蒸发一层金膜,通过调谐输入光纤光栅部位的偏振光模式来实现对外传感性能的增强。选用氯化钠溶液作为外界折射率感应物质,通过软件进行模拟仿真,仿真结果表明,镀金膜前后,横磁波和横电波的透射功率在空气中分别衰减了4.3和0.3 dB,在溶液中分别衰减了5.3和2.2 dB。在1.335~1.372溶液折射率变化范围内,两种偏振光源的折射率灵敏度分别提升了18.7和12.9 nm/RIU。

In view of the common problems of fiber surface plasmon resonance sensor with weak strength,low sensitivity and low plasma excitation efficiency,this paper proposes to use the long-period fiber grating as an auxiliary platform to study the ways of enhancing the sensitivity of surface plasmon resonance sensors.A layer of gold film is thermally evaporated on the sensing area of the fiber grating surface,and the external sensing performance is enhanced by tuning the polarization mode of the input fiber grating.We choose the sodium chloride solution as the external refractive index sensing material,and conduct a simulation through software.The results show that before and after the gold coating,the transmission power of the transverse magnetic wave and the transverse electric wave are attenuated by 4.3 and 0.3 dB in the air,and 5.3 and 2.2 dB in the solution.Within the range of refractive index change of the solution from 1.335~1.372,the refractive index sensitivity of the two polarized light sources increased by 18.7 and 12.9 nm/RIU,respectively.