We present here a theoretical analysis of the propagation of a sequence of ultrashort pulses in an optically dense medium. The interaction is resonant and treated in the weak-field regime. Dispersion is dominant and induces important reshaping effects. We show that these effects depend crucially on the relative phase shift φ between the pulses. Compared to the case of a train of independent pulses (i.e., mutually incoherent), a pulse sequence with φ=0 is shown to be sensitive to dispersion for lower optical depths, whereas a pulse sequence with φ=π is shown to be more robust.
DOI:10.1103/PhysRevA.66.065801
Voir en ligne : Phys. Rev. A 66, 065801 (2002)