Modification of self-induced transparency by a coherent control field.

We consider self-induced transparency (SIT) in a two-level atomic system in the presence of an additional control laser field. We find that the dynamics of the SIT process are profoundly modified by the control field, in a manner reminiscent of the modification of other nonlinear optical interactions through the process of electromagnetically induced transparency. The presence of the control field allows SIT to occur under a much broader range of conditions and leads to dramatically reduced values of the group velocity of the SIT soliton.