Entanglement for a general formalism of a three-level atom in an Ξ-configuration interacting nonlinearly with a non-correlated two-mode field

The degree of entanglement in the time development of a three-level atom in the Ξ-configuration interacting with a two-mode field under the mechanism of a multi-photon transition is investigated. The atom is prepared in its uppermost excited state and the fields are prepared in the binomial states. Analytical expressions for the time evolution and the reduced density operators are derived in the framework of the dressed states. Effects of mean photon numbers, detuning and the Kerr-like parameters are investigated within various forms of the intensity-dependent coupling functional. General conclusions reached are illustrated by numerical results.