Three-Axis Magnetic Field Compensation for Array OPMs Base on Cross-Coupling Suppression Model

Optically pumped magnetometers (OPMs) operating in the spin-exchange relaxation-free (SERF) regime require near-zero magnetic environment (<1 nT) to preserve high sensitivity; yet, current compensation techniques encounter difficulties with multi-axis crosstalk in array topologies. This article presents a methodology for measuring and adjusting three-axis magnetic fields to mitigate magnetic interference of array OPMs. The approach utilizes a scanning magnetic field generated by embedded coils to measure the surrounding magnetic field. A cross-coupling magnetic field compensation method is proposed to suppress cross-axis coupling in the OPM array. The compensation currents are calculated by linearly fitting a feature of the sensor’s output signal to the ambient magnetic field. The efficacy of this strategy is validated through theoretical derivation and experimental verification. The experimental results demonstrate that this approach achieves a magnetic field compensation resolution of 20 pT. The method enables rapid and precise magnetic field adjustment for OPM arrays, laying the groundwork for their application in bio magnetic detection.