High Sensitivity Magnetic Field Sensor Based on Magneto-Optical Surface Plasmon Resonance

The magnetic field sensor plays a crucial role in various fields, we have designed and developed a phase magneto-optical surface plasmon resonance (MOSPR) magnetic field sensor. We obtained the optimal film structure and polarization state of incident light by using the multilayer film reflection theory and Jones matrix to improve the sensitivity. We propose and fabricate a novel Kretschmann configuration that angular modulation of incident light with total internal reflection instead of a mirror. The new Kretschmann configuration is conducive to sensitivity, volume, and light path adjustment during the experiment. According to the simulation consequence, we prepared the phase MOSPR sensor using electron beam vaporization of Au/Co/Au film on the new type Kretschmann configuration. Moreover, the transmission electron microscope (TEM) was used to determine the energy dispersive spectroscopy (EDS) mapping of film structure, which characterized the film elements and thickness. Additionally, the different signals in the system can significantly enhance the sensor’s signal-noise ratio (SNR). The experimental results (
$25~^{\circ }$
C) based on the phase MOSPR sensor are consistent with the simulation consequence. The results have demonstrated that the phase MOSPR sensor exhibits high sensitivity (79310.3 oe/rad), ultrafast response time (< 100 ns), accuracy, and long-term stability. This sensor holds promise for applications in parameter detection in the automotive industry, navigation and positioning, geophysical magnetic fields, and environmental protection.