Development of a High-speed, Compact Magneto-optical Magnetic Field Detector

This paper presents the development and experimental validation of a high-speed, compact magnetic field detector based on the magneto-optical Faraday effect in a Terbium Gallium Garnet (TGG) crystal, illuminated by a Helium-Neon (He-Ne) laser. By leveraging the optical polarization rotation induced by external magnetic fields, the proposed detector achieves higher measurement rates and improved sensitivity compared to conventional Hall effect-based gaussmeters [4]. Hall sensors often suffer from bandwidth limitations associated with intrinsic material properties and charge-carrier mobility, as well as a drop in sensitivity and an increase in noise during miniaturization. In contrast, the magneto-optical detector presented here provides accurate, high-speed magnetic field measurements in small volumes and is ideally suited for insertion into constrained spaces. We demonstrate measurement of dynamic magnetic fields generated by a solenoid energized through an RLC discharge circuit operating in an overdamped or critically damped regime. Our results show that this optical detection approach outperforms traditional methods in both temporal response and accuracy, thereby underscoring the advantages of magneto-optical sensing in a range of magnetic field measurement applications.