Effects of Probe Laser Intensity on Co-Magnetometer Operated in Spin-Exchange Relaxation-Free Regime

The probe laser intensity working point optimization of the co- magnetometer operated in the spin-exchange relaxation-free (SERF) regime is studied theoretically and experimentally in this article. Based on the steady-state solution of the Bloch equation, the error equation of output signal considering the probe laser pumping effect is established. A method for real-time measuring the pumping rate of the probe laser on SERF co- magnetometer is presented. Combined with the measurement results, a method for quickly finding the optimal working point for the probe laser intensity is presented. The signal noise and long-term stability of the co- magnetometer under different probe laser intensities are measured experimentally to verify the accuracy of the law deduced from the theory. The results show that the pumping effect of the probe laser significantly reduces the signal-to-noise ratio of the co- magnetometer, which verifies the necessity of supplementing to error equation in this article. In addition, selecting an appropriate probe laser intensity working point can effectively reduce signal noise and bias instability of the SERF co- magnetometer.

Automated summary

This article theoretically and experimentally studies the optimization of probe laser intensity working point in the spin-exchange relaxation-free (SERF) regime for a co-magnetometer. By establishing the error equation of the output signal considering the probe laser pumping effect based on the steady-state solution of the Bloch equation, a method for real-time measuring the pumping rate of the probe laser is presented. Combined with measurement results, a method for quickly finding the optimal working point for the probe laser intensity is also proposed. The experiments verify the accuracy of the deduced law and demonstrate that an appropriate probe laser intensity working point can effectively reduce signal noise and bias instability of the SERF co-magnetometer.