"Dark state polariton" is a manifestation of inequality of forward and reversed processes in optics
V. A. Kuz’menko · arXiv (Cornell University) · 2006
The physical origin of the so-called "dark states" is connected not with the low absorption efficiency of the ground state of atoms, but with the ultra high efficiency of stimulated emission transition into the initial state. Simple pump-probe experiments for study the efficiency of the reversed transitions in a two-level system are discussed.