Analysis of a photonic crystal fiber SPR sensor based on dual polarization direction and two different metal layers

A photonic crystal fiber (PCF) with a dual-groove-based surface plasmon resonance (SPR) sensor is designed. The two grooves are positioned on the upper and right sides of the sensor. The gold (Au) and silver (Ag) films are plated on the inner walls of the two groove-shaped detection channels as the plasmonic materials. A thin layer of titanium dioxide (TiO2) is applied to the outer layer of the gold (Au) and silver (Ag) films to enhance the sensitivity of the sensor and prevent oxidation of the metal layers. The sensor designed in this paper uses different directions of polarization combined with the characteristics of different metals when the SPR effect occurs to realize the detection of two parameters. The effect of structural parameters on the sensing properties and loss spectrum is numerically analyzed by finite element method (FEM). The detection range of the refractive index sensor is from 1.36 to 1.41. In the upper channel, the maximum wavelength sensitivity (WS) can reach 14,500 nm/RIU, corresponding to a resolution of 6.90 x 10-6 RIU. In the right channel, the maximum WS can reach 13,600 nm/RIU, corresponding to a resolution of 7.36 x 10-6 RIU. The simulation results suggest that the designed dual-channel sensor can realize highly sensitive detection of two analytes simultaneously, offering wide applications in biomedical analysis and environmental monitoring. (c) 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement