Analysis of Dual-Core Photonic Crystal Fiber Based on Surface Plasmon Resonance Sensor with Segmented Silver Film

Abstract

A dual-core photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) sensor with segmented silver film (silver nanoslit) deposited in microfluidic channel is designed. The coupling characteristics and sensing performance of the proposed sensor are analyzed numerically by finite element method (FEM). The resonance intensity and wavelength sensitivity can be tuned by the segmented number and angle of the silver nanoslit, due to a strong coupling between propagation surface plasmon resonance (PSPR) on the silver film surface and local surface plasmon resonance (LSPR) at the silver nanoslit. When the segmented number is 40 and the segmented angle is 0.5°, an average sensitivity of 5100 nm/RIU is obtained in the refractive index (RI) range from 1.330 to 1.360, and is 1080 nm/RIU higher than that of continuous silver film structure under the same conditions. In addition, a maximum wavelength sensitivity of 7600 nm/RIU is achieved in the RI range from 1.355 to 1.360, corresponding to a high RI resolution of 1.32 × 10−5 RIU, which can be used to detect the slight change in the RI of an unknown analyte.