Near-infrared surface plasmon resonance sensor based on photonic crystal fiber with big open rings

A photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) is designed for near-infrared detection. The Ag-Au dual layers are selected as the plasmonic materials and the silver layer is covered by a gold layer for protection against oxidation. Influences of structural parameters on the confinement losses are investigated by the finite element method (FEM). The resonance wavelength of the sensor varies from 1470 nm to 2150 nm and a maximum wavelength sensitivity of 12400 nm/RIU and corresponding resolution of 8.06 x 10(-6) RIU are obtained for analyze refractive indexes between 1.22 and 1.36.