Atomic Frequency Comb storage as a slow-light effect
  Atomic Frequency Comb (AFC) protocol has been particularly successful recently to demonstrate the storage of quantum information in a solid medium (rare-earth doped crystals). The AFC is inspired by the photon-echo technique. We show in this paper that the AFC is actually closely related to the slow-light based storage protocols extensively used in atomic vapours. Experimental verifications are performed in thulium doped YAG (Tm3+:YAG). We clarify the interplay between absorption and dispersion and propose a classification of the existing protocols. 
M. Bonarota, J.-L. Le Gou\"et, S. A. Moiseev, T. Chaneli\`ere
quant-ph