Prospects for the use of multilambda Rabi cavities in atomic beam frequency standards

An analysis of the transition probability for an atomic beam excited by resonant microwave radiation in a TE_01n cavity fed in the center is presented. Results of the numerical integration of the Schrodinger equation and an analytical approximation obtained by means of a Magnus expansion are given. The agreement is satisfactory up to the n = 7 case, which is the highest-order examined. No asymmetry was assumed in the center feed, mainly because its effect can be shown to be very small for a cylindrical cavity, since the TE_01n mode in that kind of structure has very low losses on the side walls. The analytical and numerical results support the idea that a Ramsey cavity is not always the only solution for guiding microwaves in a beam standard