TRAPPING STATES IN A 3-LEVEL LAMBDA-SYSTEM

We study the temporal evolution and the stationary regime of an electromagnetic-field mode interacting with three-level LAMBDA-type atoms in a lossless microwave cavity. We find that under certain conditions the field evolves to the recently defined tangent or cotangent states [J. J. Slosser and P. Meystre, Phys. Rev. A 41, 3867 (1990)]. In particular, in this system number states can be generated for any value of the atomic-upper-level population. In addition, a strong squeezing in the quadrature fluctuations is found.