Forster Resonant Energy Transfer Signatures in Optically Driven Quantum Dot Molecules - Quantum Dot Molecules - page 327

Chapter 10
Forster Resonant Energy Transfer Signatures
in Optically Driven Quantum Dot Molecules
Juan E. Rolon and Sergio E. Ulloa
Abstract The present chapter discusses the optical signatures of Forster 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.
J.E. Rolon ( )
Department of Physics and Astronomy, University of North Carolina
at Chapel Hill, Chapel Hill, NC 27593-3255, USA
e-mail: [e-mail]
S.E. Ulloa
Department of Physics and Astronomy and Nanoscale and Quantum
Phenomena Institute, Ohio University, Athens, OH 45701-2979, USA
e-mail: [e-mail]