Exciton dephasing in quantum wells. Influence of spectral fluctuation processes

We perform spectrally resolved three-beam four-wave-mixing experiments in GaAs/AlGaAs quantum wells. The various resonances in these structures show very different decay parameters as a function of the delay times. A comparison with theory demonstrates that the relaxation of both polarization and population are governed by spectral fluctuations. The redistribution properties of the population are directly determined.