Surface Plasmon Resonance Refractive Index Sensor Based on Photonic Crystal Fiber with Silver Film and Titanium Dioxide Film

Abstract

A surface plasmon resonance (SPR) refractive index (RI) sensor is proposed and analyzed based on D-shaped photonic crystal fiber (PCF). A silver and titanium dioxide layer are coated on the polished surface as a sensitive layer for easy sensing and more practical implementation. The finite element simulation (FES) was applied to analyze the sensitivity of this refractive index sensor. The sensor can operate in the near-and mid-infrared region (2200-2800 nm) with analyte refractive indices in the range of 1.36-1.41. The FES analyzed results show that the resolution of the sensor is $1.35 \times 10^{-6} \mathrm{RIU}$ and the corresponding maximum wavelength sensitivity is $7400 \mathrm{~nm} / \mathrm{RIU}$. The design scheme is simple and highly sensitive, which is agreeable for sensing applications in biomedical, environmental engineering and chemical fields.