Gain-assisted superluminal light propagation via incoherent pump field

摘要

We investigate the dispersion and the absorption properties of a weak probefield in a three-level Lambda-type atomic system. We use just an incoherentfield for controlling the group velocity of light. It is shown that the slopeof dispersion changes from positive to negative just with changing theintensity of the indirect incoherent pumping field. Gain-assisted superluminallight propagation appears in this system. No laser field is used in the pumpingprocesses.