Strongly driven exciton resonances in quantum wells: Light-induced dressing versus Coulomb scattering

The nonequilibrium dynamics of a two-dimensional electron-hole gas is studi ed in the regime of strong and resonant pumping of the exciton resonance. T he Coulomb collision rates are consistently determined by taking into accou nt the light-induced coherence of the two-band system that leads to a dress ing of the carrier spectral functions. The light dressing dramatically redu ces the Coulomb scattering efficiency. Results are presented for Rabi oscil lations in the time domain and dynamical Stark splitting in the pump-probe absorption spectra.