Atom-photon entanglement dynamics near the PBG

The time evolution of the entanglement of a coherently driven V-type three-level atom, near the band edge of a photonic crystal, and its spontaneous emission field is investigated. The degree of entanglement can be modified via the intensity of the driving field and the detuning from the edge of the band gap. It is found that the quantum interference has an essential effect on the amount of quantum entropy. In addition, the atom- spontaneously emitted photon entanglement will substantially be influenced by the initial states of the atom, the coupling constants, and the relative phase between the pump and driving fields. The degree of entanglement is calculated by the quantum entropy of the system.