Light propagation in a solid with resonant atoms at random positions

Abstract

Propagation of light in media with a small density of resonant atoms at quenched random positions is studied. It is found that the transport speed is reduced substantially due to dwell effects when the atoms are close to resonance. Besides propagation of real photons, the transport channel of nonradiative transfer due to the resonance dipole-dipole interaction between excited and ground state atoms is considered. The transport equation including both transport channels is derived. The diffusion coefficient and the dielectric constant are found. The weight of the nonradiative channel increases with the density of resonant atoms, n, and becomes essential when nλ 3 approaches unity, where λ is the wavelength of the light.