  In this paper we consider a model of an atom with n energy levels interacting
with n(n-1)/2 external (laser) fields which is a natural extension of two level
system, and assume the rotating wave approximation (RWA) from the beginning. We
revisit some construction of analytical solutions (which correspond to Rabi
oscillations) of the model in the general case and examine it in detail in the
case of three level system.
