COHERENT EXCITON DYNAMICS IN GAAS-BASED SEMICONDUCTOR STRUCTURES

We show that a very powerful tool in the investigation of the coherent exciton dynamics in semiconductors is provided by the study of the em itted light after resonant excitation from pairs of phase-locked femto second pulses. Under these conditions, not only the full dynamics of t he coherent transients (dephasing times, quantum beat periods, etc.) c an be obtained from linear experiments, but it can also be obtained a straightforward discrimination between the coherent or incoherent char acter of the emission by means of spectral filtering.