Decoherence in single InAs/GaAs quantum dots

We report systematic measurements on the decoherence in single InAs/GaAs quantum dots. We demonstrate the quenching of the acoustic phonon dephasing for the fundamental interband transition. On the contrary, acoustic phonon scattering appears very efficient for the excited states because of the presence of the wetting-layer band-tail. Furthermore, we achieve a line-narrowing for the fundamental transition with linewidth of the order of few mueV by tailoring the influence of the electrostatic environment through a decrease of the excess energy in the non-resonant excitation process. We highlight the importance of controlling environmental effects on the QD optical and electronic properties in order to manipulate InAs/GaAs QDs like quasi-isolated macroatoms in solid state.