Modifications due to local field corrections of the electromagnetically induced transparency propagation parameters in a driven optically dense three-level cascade system

We compute, under conditions of electromagnetically induced transparency, the frequency dependence of the transmission coefficient and the group velocity of a probe pulse resonant with the lower transition of a three-level cascade system in the presence of a cw pump field resonant with the system's upper transition. We show that the presence of local field corrections can substantially modify the profile of both these transmission-related quantities. (C) 2000 Published by Elsevier Science B.V.