Light slowdown in the vicinity of cross-over resonances

Pulse propagation is considered in an inhomogeneously broadened medium of three-level atoms in a V-configuration, dressed by a counter-propagating pump pulse. A significant enhancement of the group index and the resulting signal slowdown are demonstrated in three frequency windows of a reduced absorption and a steep normal dispersion, in particular in that window which is due to a cross-over resonance. Particular properties of the group index in the vicinity of such a resonance are demonstrated in the case of closely spaced upper levels.