Superluminal light pulse propagation via rephasing in a transparent anomalously dispersive medium

We study the propagation of light pulses through a transparent anomalous di spersion medium where the group velocity of the pulse exceeds c and can eve n become negative. Because the medium is transparent, we can apply the Kelv in's method of stationary phase to obtain the general properties of the pul se propagation process for interesting conditions when the group velocity: U < c, U = +/-<infinity>, and even becomes negative: U < 0. A numerical sim ulation illustrating pulse propagation at a negative group velocity is also presented. We show how rephasing can produce these unusual pulse propagati on phenomena. (C) 2001 Optical Society of America.