Independent control of exciton and biexciton energies in single quantum dots via electroelastic fields

We investigate the effect of large in-plane strain and vertical electric fields on the binding energies of excitonic complexes confined in single InGaAs/GaAs quantum dots (QDs) and we find that the two independently tunable perturbations modify the interaction energies among electrons and holes in a different manner. By taking advantage of this difference, we frequency-lock the QD fundamental excitation (the neutral exciton) at a predefined value, while the biexciton transition is actively tuned from a binding to an antibinding configuration. Our electrically controlled dual-knob device demonstrates unprecedented control over the electronic properties of the few-particle states in a QD and may be applied to create novel energy-tunable sources of entangled photons using the time-reordering or the time-bin scheme.