A Two-Stage Automatic Magnetic Compensation Method With High SNR for Miniaturized SERF Atomic Magnetometers

This article presents a novel closed-loop magnetic compensation circuit system for miniaturized atomic magnetometers, which can precisely and continuously compensate residual magnetic fields to zero during closed-loop operation. First, based on the magnetic compensation principle of spin-exchange relaxation-free (SERF) atomic magnetometers, a two-stage automatic compensation method combining coarse and fine compensation is proposed, which addresses the issues of low sensitivity in active magnetic compensation and the inability to implement simultaneous array compensation. Second, the acquisition circuit, magnetic field driving circuit, and digital lock-in amplifier are improved and designed, effectively enhancing the system signal-to-noise ratio. Finally, the magnetic compensation circuit system is tested through software and hardware joint debugging, and the effectiveness of the proposed compensation method is verified through experiments. The experimental results show that the compensation performance of the designed circuit system is superior to that of commercial instruments, and the system sensitivity is improved by 31.3%.