Coherent control of light-pulse propagation in a Raman induced grating

Abstract

We study light-pulse propagation in a dynamically controllable periodic structure (grating) resulting from Raman interaction of a weak probe pulse with a standing-wave pump and a second control laser field inN-type four-level atomic media. The grating is induced due to periodic spatial modulation of the Raman gain in a standing pump field (Raman gain grating). We show that it is possible to control both the probe pulse amplitude and the group velocity of the pulse from subluminal to superluminal by varying the pump or control field. Such a grating is of interest forall-optical switches and transistors.