Förster Resonant Energy Transfer Signatures in Optically Driven Quantum Dot Molecules
The present chapter discusses the optical signatures of Förster resonant energy transfer (FRET) in optically pumped and electrically gated quantum dot molecules (QDMs). To this end, an excitonic dressed Hamiltonian is constructed and the level occupation of each exciton is calculated as function of the pump laser energy and applied electric field. Level occupation maps can offer a systematic way of identifying FRET signatures through the analysis of the spectral weight and level anticrossing behavior of each exciton that is pumped in the QDM. The resulting level occupation maps show a clear splitting of the spatially-direct excitons and nontrivial satellites following the spectral lines of the spatially-indirect excitons. These lines are clearly visible starting at the molecular resonance regime up to a regime where charge tunneling is suppressed. In this sense, FRET induces a non-trivial behavior on the spatially-indirect excitons, which is reflected by a robust signature that can be coherently controlled to avoid the detrimental effects of charge tunneling and direct exciton recombination. In addition, our work suggests that FRET optical signatures in QDMs can be addressed via pump-probe differential transmission or level anticrossing PL spectroscopy.
KeywordsExciton State Rabi Oscillation Indirect Exciton Resonant Energy Transfer Exciton Level
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