Resonance Raman scattering in photonic band-gap materials - art. no. 013814

We study the resonance Raman scattering of light from a three-level atom em bedded in a photonic band-gap material or in a frequency dispersive medium whose photon spectrum exhibits a gap due to photon coupling to medium excit ations such as excitons and optical phonons. We demonstrate that the one-pa rticle spectrum of the system consists of either a continuous part with ene rgy lying outside the gap or a single discrete mode with energy lying insid e the gap. The discrete mode, which occurs when both of the allowed atomic transitions of the Lambda configuration he inside the gap, can be treated a s a photon-atom bound state in which the radiation is localized in the vici nity of the atom. In the case of the continuous spectrum, the Rayleigh and Stokes lines are shifted as well as narrowed (or broadened) as the correspo nding transition frequencies are shifted relative to the upper band edge, p roviding a distinctive experimental signature of atom-photon interactions H ear a photonic band edge.