SCREW-TYPE TRANSPARENCY IN A 3-LEVEL MEDIUM

A solution is obtained for the system of Maxwell-Schrodinger equations describing the propagation of a laser pulse through a three-level Lam bda medium in which the initial atomic populations are in a specially prepared coherent superposition of low-energy states. This solution de scribes a new type of transparency which is characterized by the prese nce of conversion of the frequency of the incident pulse and can be us ed, specifically, to produce ''optical keys'' and frequency converters for laser radiation. (C) 1998 American Institute of Physics. [S0021-3 640(98)00811-1].