Enhancement of entanglement for two-mode fields generated from four-wave mixing with the help of the auxiliary atomic transition

The entanglement properties of two mode fields generated from four-wave mixing are discussed in the system of an ensemble of V-type three-level atoms embedded in a two-mode cavity, in which the atomic transitions from the two excited states to the ground state are driven by one strong and one relative weak laser field, respectively. The nondegenerate four-wave mixing process occurs in the strong laser-driven transition, which is also coupled by the two cavity modes. With the help of the auxiliary atomic transition driven by the weak laser field and adjusting the frequency difference of the two modes, highly squeezed and entangled light with high intensity can be generated.