Zhang Yunfang, Liao Changrui, Lin Chupao, Shao Yu, Wang Ying, Wang Yiping
Opt Lett. 2019 May 15;44(10):2434-2437. doi: 10.1364/OL.44.002434.
A novel surface plasmon resonance (SPR) configuration based on fiber-interface waveguide was proposed and realized by combining the technology of femtosecond laser writing waveguide with SPR effect for measuring refractive index (RI) of analyte. A U-shaped waveguide is inscribed in the coreless fiber and its bottom is very close to the fiber surface, which can produce strong evanescent field being sensitive to ambient media. When the fiber surface is coated with a layer of gold film, the strong evanescent field can excite the SPR effect on the fiber surface. Most importantly, different from some types of fiber SPR sensors with a fragile physical structure, the fiber-interface waveguide SPR sensor exhibits an excellent mechanical strength. Such a SPR sensor exhibits a high sensitivity of ∼3352 nm/RIU at the RI value of ∼1.395, which may have important practical applications in medicine, environmental monitoring, and food safety.
提出并实现了一种基于光纤界面波导的新型表面等离子体共振（SPR）结构，该结构通过将飞秒激光写入波导技术与SPR效应相结合，用于测量分析物的折射率（RI）。在无芯光纤中写入一个U形波导，其底部非常靠近光纤表面，可产生对周围介质敏感的强倏逝场。当光纤表面涂覆一层金膜时，强倏逝场可激发光纤表面的SPR效应。最重要的是，与一些物理结构脆弱的光纤SPR传感器不同，光纤界面波导SPR传感器具有优异的机械强度。这种SPR传感器在RI值约为1.395时表现出约3352 nm/RIU的高灵敏度，这在医学、环境监测和食品安全等方面可能具有重要的实际应用。
