High Sensitivity Surface Plasmon Resonance Magnetic Field Sensor Based on Au/Gold Nanoparticles/Magnetic Fluid in the Hollow Core Fiber

A type of surface plasmon resonance (SPR) magnetic field sensor based on Au/gold nanoparticles (AuNPS)/magnetic fluid (MF)-processed hollow core fiber is proposed in this work, which fully utilizes SPR's high sensitivity to refractive index (RI) and the magnetron RI characteristic of MF. The metal material Au excites SPR, and AuNPS excite the localized surface plasmon resonance (LSPR). The coupling of surface plasmon polariton (SPP) with localized surface plasmon (LSP) increases the local electric field strength, thus improving the sensor's sensitivity. Both the theoretical analysis on the sensing mechanism and the experimental findings demonstrate that this novel SPR magnetic field sensor has a wide measurement range and high sensitivity. In the range of magnetic field strength from 0 to 603 Gs, the sensitivity can reach up to 156 pm/Gs, and the linearity is good (the coefficient of determination is 0.996). Compared with other optical fiber magnetic field sensors, the sensor proposed in this article has the benefits of easy fabrication, excellent sensitivity, simple structure, strong anti-interference ability, and wide measurement range, thus exhibiting significant application potentials in the fields of military drills, aerospace, etc.