Magnetic field compensation method of dual-beam SERF atomic magnetometer under probing-axis bias

The traditional compensation methods for residual magnetic field in the dual-beam atomic magnetometer (DAM) operated in spin exchange relaxation-free (SERF) regime is vulnerable to probing axis bias resulting from half-wave plate adjustment error, which can lead to compensation error. In this paper, we demonstrate a novel magnetic field compensation method to circumvent the impact of probing axis bias based on the golden section method. In comparison with the traditional method, our method has been demonstrated to averagely suppress the amplitude error within the SERF DAM passband by 39.30% and to improve measurement sensitivity by 27.03% on average. Furthermore, the proposed method requires a mere 12 s to complete the automated compensation, thereby markedly enhancing the efficiency of DAM measurement system. The method exhibits superior compensation accuracy and speed, which promises to enhance the precision of source localization and reconstruction in magnetoencephalography (MEG) and magnetocardiogram (MCG) measurements based on SERF DAM arrays.