Surface plasmon resonance sensor based on photonic crystal fiber with indium tin oxide film

A novel photonic crystal fiber (PCF) sensor composed of an indium tin oxide (ITO) coating on the outer surface based on surface plasmon resonance (PCF-SPR) is designed and investigated. The sensor consists of eight air holes arranged in a rectangular grid as the cladding, the ITO layer as the plasmonic materials, and an annular external channel. The finite element method (FEM) is used to study the sensing performance and effects of different geometric parameters. The sensor can be operated in the near-infrared region (1380–2260 nm) for the analyte refractive index range between 1.26 and 1.38. In addition, the sensor shows a maximum wavelength sensitivity of 35000 nm/RIU and amplitude sensitivity of 1120.73 RIU−1. It has good wavelength and amplitude resolution reaching 2.86 × 10−6 RIU and 8.92 × 10−6 RIU, respectively and is suitable for accurate sensing applications in biomedicine and chemistry.