Two-photon detuning and decoherence in cavity electromagnetically induced transparency for quantized fields

The interaction of a quantized field with three-level atoms in Λ configuration inside a two-mode cavity is analyzed in the small-noise approximation. The atoms are in a two-photon detuning with respect to the carriers of the field. We calculate the stationary quadrature noise spectrum of the field outside the cavity in the case where the input probe field is a squeezed state and the input pump field is a coherent state. The mean value of the field is unaltered in all the analysis: the atoms shows electromagnetically induced transparency. The effect of the atoms’ base level decoherence in the cavity output field is also studied. It is found that the output field is very sensitive to two-photon detuning.