  The evolution of a Raman coupled three-level lambda atom with two quantized
cavity modes is studied in the large detuning case; i.e. when the upper atomic
level can be adiabatically eliminated. Particularly the situation when the two
modes are prepared in initial coherent or squeezed states, with a large average
number of photons, is investigated. It is found that the atom, after specific
interaction times, disentangles from the two modes, leaving them, in certain
cases, in entangled Schrodinger cat states. These disentanglement times can be
controlled by adjusting the ratio between average numbers of photons in the two
modes. It is also shown how this effective model may be used for implementing
quantum information processing. Especially it is demonstrated how to generate
various entangled states, such as EPR- and GHZ-states, and quantum logic
operations, such as the control-not and the phase-gate.
