Homogeneous linewidth of self-assembled III–V quantum dots observed in single-dot photoluminescence

We report photoluminescence emission from single self-assembled InAlGaAs quantum dots, which is broadened purely by dephasing processes. We observe linewidths as low as View the MathML source at View the MathML source, which agrees with the homogeneous linewidth derived from four-wave mixing experiments. By selecting dots that are not affected by local field fluctuations and using high-energy excitation, we avoid additional sources of linewidth broadening typically present in single-dot photoluminescence spectra. We observe a strong LO–phonon coupling in InAlGaAs and InGaAs dots, which becomes the dominating contribution to the linewidth above View the MathML source.