Three-Axis Magnetic Field Compensation for SERF Atomic Magnetometers Based on Dispersion Curve Characteristics

Spin-exchange relaxation-free (SERF) atomic magnetometers are widely recognized for their ultrahigh sensitivity in weak magnetic field measurements. However, traditional SERF magnetometers face critical limitations, where dynamic magnetic field disturbances severely degrade sensitivity. To address this challenge, we propose a three-axis magnetic compensation method based on real-time dispersion curve analysis and closed-loop control. By leveraging the symmetry characteristics of the dispersion curve, our approach identifies environmental magnetic field interference and dynamically adjusts compensation currents through a feedback mechanism. Furthermore, the integration of the Fibonacci sequence algorithm optimizes the search process for key dispersion curve nodes (e.g. extrema and zero-crossing points), significantly reducing computational complexity and accelerating compensation convergence. Experimental results demonstrate that the proposed method achieves a sensitivity of 90.1 fT/Hz<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> (improved by 64.9% compared to uncompensated systems) and suppresses magnetic noise by 87.75% in complex dynamic environments with proven long-term effectiveness. This work provides a reliable framework for highprecision SERF magnetic measurements in medical diagnostics.