Two methods to deal with inhomogenous Rabi frequency in microwave transition

We analysed the influence of inhomogenous microwave field on the coherence of atom ensembles. Two methods were proposed to suppress the dephasing generated by the inhomogenous Rabi frequency. One of them was realized by spin echo, and the other one was based on the identical spin rotation effect. The results of calculation showed that the contrast of signal acquired in experiment can be improved by the two methods. Their advantages and drawbacks were discussed. We hope they could be used to improve the contrast of experimental signal in the situation that the microwave fields are very inhomogenous. Finally, we discussed the case of continuous working microwave field and showed that the dipole force raised with the inhomogeneity can be eased by spin flip.