摘要
根据倾斜光纤光栅(TFBG)和表面镀金的TFBG传感器测量折射率的基本原理,通过OptiGrating软件模拟了不同浓度溶液下TFBG的透射谱和芯层模与某阶包层模耦合引起的谐振峰,初步得出了TFBG各阶包层模随着外界折射率的增大而向右偏移、在一定的传感范围内中心波长与外界折射率呈线性关系的结论。用小型离子溅射仪对TFBG镀45 nm厚度左右的金膜,并用扫描电镜在微观上观察镀膜效果。通过不同浓度下的NaCl溶液、MgCl_2溶液、CaCl_4溶液实验,对比研究了裸TFBG和镀金TFBG传感器对溶液折射率的传感特性。从而验证了模拟仿真得出的结论并定量分析得知:镀金后具有表面等离子体共振的TFBG溶液折射率灵敏度大于500 nm·RIU^(-1),而裸TFBG为2 nm·RIU^(-1)左右,大约提高了200~300倍,且在一定范围内中心波长与溶液折射率的线性拟合度都在0.99以上。
The present paper analyzes the sensor＇s basic principle of the bare tilted fiber Bragg grating （TFBG） and surface plas- mon resonance sensor （SPR） that deposited nanoscale gold-coating on the surface of the cladding. We simulated the transmission spectrums and some order cladding mode of TFBG in different concentration solutions by Integration and optical fiber grating software OptiGrating. So by the graphic observation and data analysis, a preliminary conclusion was got that in a certain sensing scope, the cladding modes of TFBG shift slightly to right with the increasing the solution refractive index（SRI）, and the relation between resonance peak caused by the coupling of core mode and a certain cladding mode and the SRI was linear. Then the 45 am thick gold coating was deposited on the surface of the TFBG cladding in a small-scale sputtering chamber KYKY SBC-12, and thermal field scanning electron microscopy presents that the effect of gold-coating was satisfactory to a certain extent in terms of microscopic level . The refractive index（RI） sensing experiments of different concentration solutions of NaC1, MgC12, CaC12 were carried out using bare and gold deposited TFBG. The RI sensing characteristics of both bare and gold deposited TFBGs re- spectively were studied by experiments. Meanwhile, it proved the conclusion that the cladding modes of TFI drifted to right gradually when the SRI was increasing and the relations between resonance peak caused by the coupling of core mode and a cer- tain cladding mode and the SRI were linear. And by quantitative analysis, we know that SPR sensor with the deposited namoscale gold layer on the surface of cladding enhanced the RI sensitivity dramatically by 2 to 500 nm · RIU-1 which is 200 to 300 times larger than that of the bare tilted fiber Bragg grating approximately. The degrees of linear fittings of resonance peak caused by the coupling of core mode and a certain cladding mode and SRI of bare and gold-coating deposited SPR sensor are very good and both of them reach up to more than 0. 99.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2013年第12期3425-3431,共7页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(61271073)
教育部新世纪优秀人才计划项目(NCET-10-0541)
山东大学自主创新基金项目(2012ZD015
2012JC008)资助
关键词
倾斜光纤光栅
金膜
表面等离子体共振
折射率传感器
Titled fiber Bragg grating
Gold-plating
Surface plasmon resonance Refractive index sensor
