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

The nonequilibrium dynamics of a two-dimensional electron-hole gas is studied in the regime of strong and resonant pumping of the exciton resonance. The Coulomb collision rates are consistently determined by taking into account the light-induced coherence of the two-band system that leads to a dressing of the carrier spectral functions. The light dressing dramatically reduces the Coulomb scattering efficiency. Results are presented for Rabi oscillations in the time domain and dynamical Stark splitting in the pump-probe absorption spectra

Coherence versus Coulomb scattering in resonantly excited quantum wells

The role of Coulomb scattering is studied in the coherent transients of strongly driven exciton resonances in semiconductor quantum wells. Coulomb scattering is treated within the second Born approximation and the light-induced dressing of the electron-hole gas is consistently included. The light dressing is found to decrease the Coulomb collision efficiency and therefore the field-driven dynamics is close to the Hartree-Fock case. Indeed, Coulomb relaxation and dephasing are not strong enough to prevent a dynamical Stark splitting in the pump-probe absorption spectra

Photoluminescence spectra in semiconductor confined systems: Effects of Coulomb correlation

The interacting electron-hole system is investigated in the framework of non-equilibrium Green's functions. Using the Bethe-Salpeter equation in the ladder approximation we derive a set of equations for the polarization of the interacting electron and hole system. By solving these equations we reproduce the photoluminescence spectrum for a continuous wave excitation. Calculations are performed in the one-dimensional case using a contact potential for electron-hole interaction, which allows to perform most of the steps of the calculations analytically. The main features of the one dimensional Coulomb correlation, namely the exciton blue drift due to phase space filling; and the Sommerfeld factor are reproduced. The dependence of the spectra on the density and energy of the pump is discussed