Resonant transmission spectroscopy on the p to p transitions of a charge tunable InGaAs quantum dot

We have performed resonant interband transmission spectroscopy on the transitions between the s-shells and the p-shells of a single charge tunable InGaAs quantum dot (QD). In contrast to the s-shell spectroscopy, investigating p-shell transitions allows the study of a QD charged with up to four electrons. The exciton charging state is clearly identified as a function of gate voltage ranges. In contrast to the s-shell, the p-shell electronic states show a strong tunnel coupling to the Fermi sea of the back contact.