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 (ITO) 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 (MF) for magnetic field detection. Additionally, a temperature and refractive index sensitive material polydimethylsiloxane (PDMS) 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 0~12Oe is 11.1nm/Oe, the highest temperature sensitivity in the range of 20~400℃ is -0.5nm/℃, and the highest refractive index sensitivity in the range of 1.17~1.35μm is 1000nm/RIU. 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, geological and environmental assessments.