Spontaneous Emission Spectrum from a Driven Three-Level Atom in a Double-Band Photonic Crystal.

The spontaneous emission spectrum from a driven three-level atom placed inside a double-band photonic crystal has been investigated. We use the model which assumes the upper levels of the atomic transition are coupled via a classical driving field. The transition from one of the upper levels to lower level couples to the modes of the modified reservoir, and the transition from the other upper level to lower level interactwith the free vacuum modes. The effect of classical driving field on the spontaneous emission spectrum of this latter transition is investigated in detail. Most interestingly it is shown that only in the presence of the classical driving field; there is a black dark line in the spontaneous emission spectrum of free-space transition when the modified reservoir is of the photonic band gap type. This dark line is not seen in the case where the modified reservoir is of the free space type for relatively weak driving field.