Potentialities of an Electro-Optic Crystal Fed by Nuclear Magnetic Resonant Resonant Coil for Remote and Low-Invasive Magnetic Field Characterization

In this paper, we demonstrate the use of a LiTaO₃ crystal associated with a typical nuclear magnetic resonant loop coil to perform an optically remote radio frequency magnetic-field characterization. The whole transduction scheme is theoretically and experimentally studied. The measurement dynamics reaches 60 dB. The minimum detectable magnetic field is lower than 1 nT, which corresponds to an induced inner crystal electric field as low as 30 mV/m. To evaluate the spatial potentialities of the sensor, a 1-D mapping of the field along an asymmetric butterfly-shaped loop coil is performed. The result is in good agreement with finite-difference time-domain simulations and demonstrates the vectorial behavior of the sensor device.