Probing excitons and biexcitons in coupled quantum dots by coherent two-dimensional optical spectroscopy

摘要

We calculate two-dimensional (2D) photon-echo and double-quantum-coherence spectra of two coupled InGaAs/GaAs quantum dots at various distances, taking into account electron, hole, and exciton hopping. Signatures of direct and indirect excitons in two-exciton resonances are revealed. At short distances, electron delocalization contributes to the creation of new biexcitonic peaks, and dipole-dipole interactions shift the two-exciton energies.