Magnetic field gradient in K–Rb–²¹Ne comagnetometer: Measurement, decoupling and suppression

Magnetic field gradients affect the signal-to-noise ratio of the spin-exchange relaxation-free gyroscopes (SERFG), thereby affecting sensitivity and long-term stability. A novel method to in situ measure, decouple and suppress the effect of magnetic field gradient on relaxation rate of SERFG is studied. The total magnetic field gradient is in situ measured by fitting the relationship between magnetic field gradient (applied by magnetic field coil) and relaxation rate method, and the effects of magnetic field gradients generated by electron spin polarization and those generated by inhomogeneous distribution of the residual magnetic field on the relaxation rate of SERFG are separated by turning the pump light on and off. The experimental study demonstrates that the magnetic field gradient in the atomic vapor cell is compensated by a self-developed magnetic field gradient coil to reduce the effect on the nucleon spin relaxation rate, and that the sensitivity and bias instability of SERFG are improved due to the in situ measurement, decoupling and compensation of the magnetic field gradient. This study lays the path for effectively improving the performance index and practical application potential of SERFG.