Highly Sensitive U-Shaped Optical Fiber Refractometer Based on Bi2O2Se-Assisted Surface Plasmon Resonance

In this work, we first used a new 2-D semiconductor material Bi2O2Se for optical fiber surface plasmon resonance (SPR) sensor sensitization, proposed, and validated a U-shaped optical fiber SPR sensor with Au film-Bi2O2Se sandwich structure. The finite element simulation results illustrate that the electric field strength on the surface is 2.08 times higher than that of the pure Au film, which excites a stronger SPR phenomenon thus leading to a high sensitivity of the sensor. The effect of the radius on the sensor performance was investigated, and the optimal structural parameters were derived to fabricate the sensing probes. The RI sensitivity of the presented sensor is 6827.41 nm/RIU, 1.98 times superior to that of the pure Au film U-shaped optical SPR sensor. The sensor is insensitive to temperature fluctuations and has good repetitive and environmental stability. The proposed sensor has good potential for future applications in biomass detection, which also indicates that Bi2O2Se has good prospects for future applications in optoelectronic devices.