The effect of fine structure on the spontaneous emission, absorption-dispersion spectra of a four-level atom in a photonic crystal

In this paper, the effect of fine structure of lower level of atomic transition on the spontaneous emission and the probe dispersion-absorption spectra of a four-level atom in photonic crystal have been studied. It is assumed that one of the three atomic transitions in an atomic system is interacting with free vacuum modes, and the two other transitions (including fine structure) are interacting with photonic band gap modes. It is shown that the spontaneous emission and the probe dispersion-absorption spectra can be controlled by tuning of the frequency distance between the fine structure levels.