Dynamics of Two Overlapping Spin Ensembles Interacting by Spin Exchange with Large Rb Magnetization Field

Two spin ensembles which occupy the same volume in a spherical alkali vapor cell can coupled together by the spin exchange interaction. In a K-Rb-$^{21}$Ne co-magnetometer which was used for rotation sensing, Rb atomic spins and the $^{21}$Ne nuclear spins couple together by spin exchange. Due to the large Rb density and the Fermi contact constant of Rb-$^{21}$Ne pair, the magnetization field of Rb atomic spins is much larger than that of the K in a K-$^{3}$He co-magnetometer. At the co-magnetometer working point, the precession frequency of Rb atomic spins are much larger than that of the $^{21}$Ne spins. The decay rate and precession frequency of $^{21}$Ne atoms is much smaller than that of the point when the precession frequencies of the Rb and $^{21}$Ne atoms are the same. In this experiment, the dynamics of the Rb- $^{21}$Ne pair at different holding magnetic field point were studied. The frequency response of the co-magnetometer to oscillating magnetic field at different holding magnetic field point was also studied.