High-sensitivity ring-core photonic crystal fiber sensor based on surface plasmon resonance for ultra-low refractive index detection

A novel ring-core photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) is designed for ultra-low refractive index detection. A gold nanowire is coated on the outer surface of the PCF as a plasma material, greatly facilitating the manufacturing of the sensor. To achieve real-time detection, the analyte is located on the outside of the sensor. The mode coupling effect and main performance parameters are analyzed through finite element method. In addition, by optimizing several important structural parameters, the overall performance of the sensor has been greatly improved. The optimized sensor shows a maximum wavelength sensitivity of 26,000[Formula: see text]nm/RIU in the refractive index range of 1.14–1.26, maximum amplitude sensitivity of 300[Formula: see text]RIU[Formula: see text], as well as minimum resolution of [Formula: see text][Formula: see text]RIU. The PCF-SPR sensor with outstanding properties has great potential in applications such as oil logging, biosensing, and chemical monitoring.