High Sensitivity of Refractive Index Sensor Based on Analyte-Filled Photonic Crystal Fiber With Surface Plasmon Resonance

Two kinds of novel plasmonic high sensitivity of refractive index (RI) sensors based on analyte-filled photonic crystal fiber (AF-PCF) are proposed in this paper. The metallic gold and silver is used as the surface plasmon resonance activity metal. A full-vector finite-element method is applied to analyze and investigate the sensing and coupling characteristics of this designed AF-PCF with the gold or silver layer. Phase matching between the second surface plasmon polariton and fundamental modes can be met at different wavelengths as the analyte of the RI is increased from 1.40 to 1.42. The phase-matching wavelength of the designed AF-PCF with the gold layer is shifted to the longer wavelength direction compared with that with the silver layer, and the resonance strength is much stronger. The average sensitivities of 7040 and 7017 nm/RIU in the sensing are arranged from 1.40 to 1.42 with high linearity are achieved for the designed sensors with the gold and silver layers, respectively, which are almost the same. However, the figure of merit with the silver layer is much better than that with the gold layer.