We study the one-dimensional propagation of a laser pulse through an atomic vapor of finite length L. Both the temporal and the time-dependent spectral profiles of the exiting laser pulse are calculated. It is shown that, when the pulse duration is comparable with or shorter than the effective relaxation time of the atomic density matrix, the spectrum of the final pulse exhibits frequency sidebands located in the vicinity of the time-varying generalized Rabi frequency, which can contain up to a few percent of the total laser power. The possible connection between this result and cone emission in the pulsed regime is addressed.

• Received 28 June 1995

DOI:https://doi.org/10.1103/PhysRevA.52.R3440