Analysis and suppression of magnetic field interference for SERF atomic magnetometer

In this study, the main sources of magnetic field interference facing single-beam spin exchange relaxation free (SERF) atomic magnetometer are first modeled and analyzed, defining their nonlinear effects and identifying the suppression conflict with signals to be measured. To solve the problems, the active disturbance rejection control system is established and improved by introducing the phase-leading network, implementing bandwidth enhancement of SERF atomic magnetometers while maintaining the resonance peak comparable to the proportional-integral control system. The interference suppression effectiveness is compared and the optimal parameters are tuned by comprehensive consideration of various indicators. The nonlinear effect of DC magnetic field interference is reduced from 16.5% to 4.8%. In addition, we carry out the measurement and correlation analysis of the cardiac-magnetic signals and analyze the differences in the suppression effectiveness of the multi-channel closed-loop magnetometers experimentally.