Stabilized control of electron polarization based on optical rotation feedback in the SERF co-magnetometer

Electron polarization fluctuations limit the long-term stability of the spin-exchange relaxation-free co-magnetometer (SERFCM) output. To address this issue, this paper proposes what is, to our knowledge, a novel method for the non-destructive measurement of electron polarization based on optical birefringence, combined with real-time control to stabilize it. This approach requires no additional excitation, avoiding interference with the system’s state and performance. A model is developed to quantify the impact of electron polarization fluctuations on inertial measurements, revealing the influence of polarization stability on the system’s scale factor and magnetic field suppression capability. In the experimental implementation, an optical rotation-based feedback technique is utilized to dynamically adjust the pump laser wavelength, enabling stable regulation of electron polarization. This approach effectively mitigates the impact of laser wavelength drift and low-frequency power fluctuations, thereby substantially improving the long-term stability of the SERFCM.