光子学报, 2017, 46 (10): 1006004, 网络出版: 2017-11-24
基于U型结构的单模光纤SPR折射率传感器
Single Mode Fiber SPR Refractive Index Sensor Based on U-shaped Structure
光纤传感器 表面等离子体共振 有限元方法 电介质薄层 多层膜 Fiber optic sensors Surface plasmon resonance Finite element method Dielectric films Multilayer films
摘要
设计了一种基于U型结构的单模光纤表面等离子体共振折射率传感器, 采用在移除部分包层并弯曲成U型固定后的单模光纤表面镀金纳米层和TiO2调制层的方式, 实现表面等离子体共振的激发.利用有限元仿真软件COMSOL Multiphysics, 研究了不同弯曲半径和TiO2调制层厚度对传感性能的影响.通过对四种弯曲半径(R=0.3 cm,0.5 cm,0.8 cm,1 cm)的分析, 结果表明随着弯曲半径增大, 表面等离子体共振信号强度增大且峰值波长有微小的蓝移.在弯曲半径为0.5 cm的条件下, 研究了TiO2调制层厚度从0变化到40 nm对传感器性能的影响, 结果表明随着TiO2调制层厚度增大, 表面等离子体共振峰峰值波长红移且对外界折射率变化的灵敏度显著增大.在弯曲半径为0.5 cm, TiO2调制层厚度为40 nm的条件下, 传感器在低折射率区(nd=1.333)灵敏度达到了5 959 nm/RIU, 高折射率区(nd=1.383)灵敏度达到了11 092 nm/RIU.与没有调制层的结果相比, 灵敏度提高了一倍左右.
Abstract
A single-mode fiber surface plasmon resonance refractive index sensor based on U-shaped structure was designed. The sensor is fabricated by coating the gold nanometer layer and the TiO2 modulation layer on the surface of single-mode optical fiber whose cladding is partiallyremoved and then isbent into U-shape. The impact of different bending radius and thickness of TiO2 on the sensing performance was studied by using finite element simulation software COMSOL Multiphysics. Through analyzing four different bend radii(R=0.3 cm,0.5 cm,0.8 cm,1 cm), we found that with the increase of the bending radius, the surface plasmon resonance signal intensity increases and the peak shifts to shorter wavelength slightly. The performance of the sensor with different thickness of the TiO2 modulation layer from 0 to 40 nm was studiedunder the condition of bending radius of 0.5 cm. With the increase of the thickness of the TiO2 modulation layer, the surface plasmon resonance peak shifts to longer wavelength and the sensitivity of the peak to the analyte refractive index increases significantly. The sensitivity of the sensor in the low refractive index region (nd=1.333) reached 5 959 nm/RIU and the sensitivity of the high refractive index region (nd=1.383) reached 11 092 nm/RIU at the bending radius of 0.5cm and the thickness of the TiO2 modulation layer was 40nm. Compared with the results of no modulation layer, the sensitivities increase by about doubled.
薛萌, 刘琨, 王涛, 常鹏翔, 江俊峰, 刘铁根. 基于U型结构的单模光纤SPR折射率传感器[J]. 光子学报, 2017, 46(10): 1006004. XUE Meng, LIU Kun, WANG Tao, CHANG Peng-xiang, JIANG Jun-feng, LIU Tie-gen. Single Mode Fiber SPR Refractive Index Sensor Based on U-shaped Structure[J]. ACTA PHOTONICA SINICA, 2017, 46(10): 1006004.