Etude des effets spectraux et spatiaux liés à la propagation d'un faisceau laser resonnant dans une vapeur de baryum

Abstract We present some characteristic features of the interaction between a resonant laser pulse and a dense atomic medium (barium vapor). A spectral analysis of the coherent transmitted light displays side bands related to the Rabi frequency. A study of the spatial behaviour of the laser beam shows that light filaments are generated and we specify in what experimental situation (light intensity, atomic concentration) this phenomenon takes place. Starting from Maxwell-Bloch equations for a resonantly driven two-level atomic system we built a computation code whose numerical results are in good agreement with our experiments.