In Situ Calibration of Coils Constant in a Spin-Exchange Relaxation-Free (SERF) Co-magnetometer

We demonstrated an in situ calibration method of magnetic field coils constant in an atomic co-magnetometer based on the pumping effect of the probe laser, which is an effective technique to assist the calibration of coils constant and suppress the inaccuracy arose from the fluctuation of the temperature. With this method, the measured coils constant is 44.10 ±0.71 nT/mA in Y-axis. Moreover, the scale factor K between voltage and internal signal also could be corrected from 0.538 ± 0.009 °/s/V to 0.798 ± 0.016 °/s/V. And the results indicate the higher sensitivity of a SERF co-magnetometer could be achieved with the assisted coils constant. In addition, it can also be used in a no destructive way to decrease the influence of other parts in the device and increase the measured accuracy. Furthermore, it is an achievable method to be applied into a K-Rb-²¹Ne co-magnetometer whereby the magnetic field shielding condition and SERF regime of alkali-metal atoms will not be destructed.