Beschreibung:
<jats:p>Using an infrared tunable femtosecond source, we investigate the time evolution of exciton absorption bleaching in InGaAs/InP quantum wells at energies slightly below the exciton absorption peak at room temperature. We find that the bleaching due to photogenerated excitons can be stronger than that due to a thermal electron/hole plasma by a factor of 40. Numerical modeling, based on many-body theory, yields a qualitative explanation of this unusual behavior, along with its density and spectral dependence as well.</jats:p>