Interferometric coherence measurement of stress-inducedInxGa1−xA

Dephasing of the lowest-energy electronic transition of In0.1Ga0.9As/GaAs stress-induced quantum dots in inhomogeneously broadened system has been investigated by the interferometric double pulse excitation and time-integrated detection of optical-phonon sideband in their resonant-photoluminescence spectra. It was found that combination of the narrow phonon resonance and spectral filtering of the signals allow us to determine the dephasing time in inhomogeneously broadened ensemble of quantum dots. The dephasing time of about 100 ps at 2 K shows that a pure dephasing is still essential in the studied system, most likely, as a result of coupling of electronic excitations in quantum dots with optical phonons of surroundings via deformation potential