Simultaneous tri-parameter surface plasmon resonance photonic crystal fiber sensor

Abstract This study presents a photonic crystal fiber (PCF) integrated with a surface plasmon resonance (SPR) sensor that utilizes two orthogonal polarization core modes for sensing. The PCF features a thin indium tin oxide layer on the inner channel and lower polished surface, an upper polished surface with a thin gold film, and an inner channel filled with magnetic fluid for magnetic field detection. Additionally, a temperature and refractive index sensitive material polydimethylsiloxane is placed on the lower polished surface, while the upper polished surface is designed for refractive index measurement. This multifunctional PCF-SPR sensor offers a compact and efficient solution for simultaneous detection of magnetic fields, temperature, and refractive index variations. The highest magnetic field sensitivity in the range of 0 ∼ 12 Oe is 11.1 nm/Oe, the highest temperature sensitivity in the range of 20 ∼ 400 °C is −0.5 nm °C −1 , and the highest refractive index sensitivity in the range of 1.17 ∼ 1.35 μ m is 1000 nm RIU −1 . The designed sensor effectively mitigates the cross-sensitivity issues during concurrent measurements of the magnetic field, temperature, and refractive index simultaneously, presenting significant potential for applications in complex environment, including mineral resource exploration, biochemical analysis, defense weapon manufacturing, geological and environmental assessments.