A wide measurement range plasmonic refractive index sensor based on side-polished photonic crystal fiber

Abstract

A wide measurement range plasmonic refractive index (RI) sensor based on side-polished photonic crystal fiber (PCF) was proposed and studied in this paper. A composite film containing an Au layer and a TiO2 layer was coated on the polished surface of PCF to excite and modulate the surface plasmon resonance (SPR) effect. The sensing characteristics were analyzed using the finite element method (FEM). Numerical results showed that the sensing performances were significantly improved through introducing the unique optoelectronic material of TiO2 film. The designed RI sensor showed an ultra-wide measurement range of 1.20–1.38 with a highest sensitivity of 14600 nm RIU−1. The best resolution (R) and figure of merit (FOM) reached 6.85 × 10−6 RIU and 224.62 RIU−1, respectively. The designed side-polished PCF which is coated with an optimized TiO2/Au composite membranes has a promising performance in the field of RI sensing requiring high sensitivity and wide range monitoring.