Kim Hyun-Tae, Yu Miao
Department of Mechanical Engineering, University of Maryland, College Park, Maryland, 20742, USA.
Sci Rep. 2019 Feb 13;9(1):1922. doi: 10.1038/s41598-018-38113-1.
Surface plasmon resonance (SPR) based sensing is an attractive approach for realizing lab-on-fiber nanoprobes. However, simultaneous measurement of multiple parameters (e.g., refractive index and temperature) with SPR-based nanoprobes, although highly desirable, is challenging. We report a lab-on-fiber nanoprobe with dual high-Q Rayleigh anomaly (RA)-surface plasmon polariton (SPP) resonances for multiparameter sensing. To achieve high-Q RA-SPP resonance the nanoprobe employs a plasmonic crystal cavity enhanced by distributed Bragg reflector (DBR) gratings on the end-face of a single-mode optical fiber. By tailoring the grating periods of the plasmonic crystal cavity and DBRs, two spatially separated high-Q RA-SPP resonance modes are designed within a 50 nm spectral range in C + L band. The fabricated nanoprobe demonstrates two RA-SPP resonances near 1550 nm with high Q-factors up to 198. These two high-Q resonances are further showed to exhibit distinctive responses to the changes of refractive index and temperature, which enables simultaneous measurements of both parameters. The proposed lab-on-fiber nanoprobes will pave the way for realizing compact multiparameter sensing solutions compatible with optical communication infrastructures.
基于表面等离子体共振（SPR）的传感是实现光纤纳米探针实验室的一种有吸引力的方法。然而，使用基于SPR的纳米探针同时测量多个参数（例如折射率和温度），尽管非常理想，但却具有挑战性。我们报道了一种用于多参数传感的具有双高Q值瑞利异常（RA）-表面等离子体激元（SPP）共振的光纤纳米探针。为了实现高Q值的RA-SPP共振，该纳米探针采用了一种等离子体晶体腔，该腔由单模光纤端面上的分布式布拉格反射器（DBR）光栅增强。通过调整等离子体晶体腔和DBR的光栅周期，在C+L波段的50nm光谱范围内设计了两个空间分离的高Q值RA-SPP共振模式。所制备的纳米探针在1550nm附近展示了两个RA-SPP共振，其Q值高达198。进一步表明，这两个高Q值共振对折射率和温度的变化表现出独特的响应，从而能够同时测量这两个参数。所提出的光纤纳米探针将为实现与光通信基础设施兼容的紧凑型多参数传感解决方案铺平道路。
