Spontaneous emission from an atom in a photonic crystal with two coherent bands

The dynamic and the radiative properties of an excited three-level atom embedded in an anisotropic photonic crystal with two coherent bands are investigated. The relative position of the atom in a Wigner--Seitz cell is described with a position-dependent parameter θ(r ₀), which is used as the coherent parameter for the two bands. The result shows that the dynamic properties of the atomic system are not only determined by atomic transition frequencies, but also affected by the gap width and the coherence of the two bands. In addition, the spontaneous emission spectrum of the atomic transition in free space is discussed. The center and the intensity of the spectrum can be obviously manipulated via the coherent parameter.