Surface plasmon resonance sensor for low refractive index detection based on microstructured fiber

A surface plasmon resonance sensor based on microstructured fiber (MSF) is proposed for low refractive index (RI) detection in the range of 1.20-1.34. The MSF is composed of substrate and sector air rings with negative curvature. Gold is coated on the external cladding surface. A finite element method is applied to analyze the performance of the sensor. Results show that the sensor is independent of polarization, and the resonance wavelength has a negative shift with RI variation in the near-infrared (near-IR) spectrum. The average sensitivity is -8892 nm/RIU, and the maximum resolution is 6.54 x 10(-6). Owing to the high sensitivity in the low RI range, the sensor offers a promising approach for water pollution measuring, humidity monitoring, and liquid concentration testing. (C) 2019 Optical Society of America