Single photon emission is investigated for fast radiative quantum dots. A simple model including capture process shows that the probability that a second photon is emitted increases when decreasing the exciton radiative lifetime. This effect is experimentally demonstrated through photon correlation measurements on single GaAs quantum dots presenting various radiative lifetime. The same model is used to estimate the second order autocorrelation function for an InAs quantum dot experiencing strong Purcell effect. The calculation shows the limitations of using Purcell effect to realize efficient single photon sources. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photon correlation measurements are performed on single GaAs quantum dots with various excitonic radiative lifetimes. A continuous increase of the probability that the quantum dot emits more than one photon per excitation pulse is observed when decreasing the exciton radiative lifetime. The authors show that this increase is due to recapture processes into the quantum dot. A model for the second-order autocorrelation function including relaxation processes is developed and gives good description of the experimental observations.

To demonstrate strong coupling regime for a single quantum dot inside an optical microcavity, large oscillator strength quantum dots are needed. We show that quantum dots formed by the interface fluctuations of a thin GaAs quantum well are ideal systems for this purpose since they can present an oscillator strength larger than 100. By inserting a GaAs QD inside a state of the art microdisk microcavity, we demonstrate the strong coupling regime with a Rabi splitting of 400 mu eV. (C) 2006 WrLEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

We report on time resolved measurements on single monolayer fluctuation GaAs quantum dots. We measure radiative lifetimes as short as 100 ps for the exciton. Studying various single quantum dots, we demonstrate that the radiative lifetime of the exciton is controlled by the quantum dot lateral size.

We report on photoluminescence on single GaAs quantum dots. We show that, because the quantum dots have short radiative lifetime, the biexciton line is composed of various contributions originating from the Coulomb interaction with higher energy excitons. This appears as a broad low energy sideband on the biexciton line, that appears whenever the biexciton is observed. A simple model allows us to account for our observations and to show that this sideband is the spectral signature of ultra fast quantum dots in continuous wave measurements.

We report on time-resolved measurements on single GaAs quantum dots formed at the interface fluctuation of a GaAs/AlGaAs quantum well. We measure exciton radiative lifetimes as short as 100 ps, demonstrating that monolayer fluctuation quantum dots have larger oscillator strength than any other III-V or II-VI semiconductor quantum dots. Studying various single quantum dots, we demonstrate that the oscillator strength of a quantum dot is controlled by its lateral confinement energy.

We report on the observation of the strong-coupling regime between the excitonic transition of a single GaAs quantum dot and a discrete optical mode of a microdisk microcavity. Photoluminescence is performed at various temperatures to tune the quantum dot exciton with respect to the optical mode. At resonance, we observe a clear anticrossing behavior, signature of the strong-coupling regime. The vacuum Rabi splitting amounts to 400 microeV and is twice as large as the individual linewidths.

We report on photoluminescence measurements on single GaAs monolayer fluctuation quantum dots. We show that, because the quantum dots have short radiative lifetime, the biexciton line is composed of various contributions originating from the Coulomb interaction with higher energy excitons. This appears as a broad low energy sideband on the biexciton line which appears for an average number of excitons in the system as small as 0.3. A simple model allows us to account for our observations and to show that this sideband is the spectral signature of fast quantum dots in continuous wave measurements.

We report on temperature dependent photoluminescence measurements on single monolayer fluctuation GaAs/AlGaAs quantum dots. At low temperature, the exciton lineshape deviates from the expected Lorentzian profile, with the appearance of asymmetric acoustic phonon sidebands. The temperature dependence of the exciton lineshape and its asymmetry, are very well accounted by a model describing the non-perturbative coupling with acoustic phonons. The effect of confinement on these phonon sidebands is finally adressed.

We report on the observation of asymmetric phonon sidebands on both the exciton and biexciton emission lines in single GaAs monolayer fluctuation quantum dots. The contribution of phonon sidebands to the emission line is larger for the biexciton than for the exciton. We model the exciton line shape by means of a nonperturbative coupling with acoustic phonons and show that energetic confinement is an important clue to understand why phonon sidebands are sometimes observed and sometimes not. Finally, we discuss the extension of our model to the biexciton case.

We report on photon correlation measurements on a single quantum dot formed at fluctuations of the interface of a GaAs/GaAlAs quantum well. We demonstrate that under pulsed nonresonant excitation, the quantum dot emits a single photon per pulse. This shows that after the photon emission, there is no refill of the quantum dot by the nearby two-dimensional reservoir of delocalized states. The possibility of delivering Fourier transform limited single photons makes this system a good candidate for exciton- and photon-based quantum information processing schemes.