Interband light absorption and Pauli blocking in InAs/GaAs quantum dots covered by InGaAs quantum wells

Spectra of interband light absorption in InAs/GaAs quantum dots covered by InGaAs quantum wells were investigated experimentally and theoretically. The main peaks in the spectra are connected with electron transitions between ground and excited quantum dot states. The value of an interband absorption cross section was determined. Interband light absorption was also studied under the conditions of interband optical pumping. The photoinduced change of interband absorption for polarized light was studied as a function of interband optical pump intensity and the light amplification was found. The change of absorption, including light amplification, is caused by the occupation of quantum dot states with non-equilibrium electrons and holes.