Application and Performance Improvement of an Optical Power Stabilization System Based on MEMS-LCVR in a SERF Atomic Magnetometer

A stabilization method utilizing MEMS technology combined with a liquid crystal variable retarder (LCVR) was developed to enhance fiber laser output power stability and was applied to a spin-exchange relaxation-free (SERF) atomic magnetometer. Comparative experiments demonstrated that the unstabilized laser output exhibited 2.8% power fluctuations over a 500 s period, while the stabilized laser reduced this to 0.2%. Spectral density analysis confirmed suppressed frequency-domain fluctuations, indicating improved robustness against disturbances. Furthermore, the stabilized laser also reduced optical noise in SERF magnetometry, achieving a sensitivity of 19.2fT/Hz1/2. These results validate that the method optimizes both time- and frequency-domain performance, thereby advancing high-precision SERF magnetometry.