Suppression of Crosstalk in Optically Pumped Magnetometer Arrays via Sensitive Axis Manipulation

Optically pumped magnetometers (OPMs) based on the spin-exchange relaxation-free (SERF) regime are advancing toward a high-density array for wearable magnetoencephalography (MEG) applications. However, modulation field crosstalk in multichannel OPM arrays can induce sensitive axis orientation error (SAOE). To address this challenge, we propose a suppression method that leverages the unimodal relationship between the static magnetic field along the pumping axis (SMFPA) and the rotation angle of the sensitive axis. By adjusting this static field for each OPM independently, we manipulate the sensitive axis to minimize the SAOE of all OPMs in the array. Experiments on a heterogeneous eight-channel array achieved 87% average SAOE suppression, with OPM sensitivity showing an average improvement of approximately 33%. The results demonstrate that the proposed method is robust against residual field variations and additional modulation interference, effectively suppressing SAOE and improving OPM performance, which may benefit high-density, wearable OPM-MEG systems.