Optical absorption spectra of a quantum dot in a microcavity (original) (raw)
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On the spectroscopy of quantum dots in microcavities
2010
At the occasion of the OECS conference in Madrid, we give a succinct account of some recent predictions in the spectroscopy of a quantum dot in a microcavity that remain to be observed experimentally, sometimes within the reach of the current state of the art. Light-matter coupling of a single quantum dot in a microcavity has recently enjoyed considerable activity. Led by sustained technological progress, various groups now control strong coupling (see Refs. [1; 2; 3; 4] for some recent reports, and references therein). From a "naive" reading of the figures in the literature, one can establish a rough picture of the state of the art, positioning various systems (and various groups) in terms of the cavity, γ a , and exciton, γ b , decay rates, in units of the coupling strenght g. This is shown in the inset of Fig. 1. The closer the system to the origin, the better it is to exhibit quantum phenomena. We shall consider in this text (and its supporting media animations) three sets of parameters:
Optical spectra of a quantum dot in a microcavity in the nonlinear regime
Physical Review B, 2008
The optical emission spectrum of a quantum dot in strong coupling with the single mode of a microcavity is obtained in the nonlinear regime. We study how exciton-exciton interactions alter the emission spectrum of the system, bringing the linear Rabi doublet into a multiplet structure that is strongly dependent on the cavity-exciton energy detuning. We emphasise how nonlinearity can be used to evidence the genuine quantum nature of the coupling by producing satellites peaks of the Rabi doublet that originate from the quantized energy levels of the interactions.
Dynamics of the excitations of a quantum dot in a microcavity
Physical Review B, 2004
We study the dynamics of a quantum dot embedded in a three-dimensional microcavity in the strong coupling regime in which the quantum dot exciton has an energy close to the frequency of a confined cavity mode. Under the continuous pumping of the system, confined electron and hole can recombine either by spontaneous emission through a leaky mode or by stimulated emission of a cavity mode that can escape from the cavity. The numerical integration of a master equation including all these effects gives the dynamics of the density matrix. By using the quantum regression theorem, we compute the first and second order coherence functions required to calculate the photon statistics and the spectrum of the emitted light. Our main result is the determination of a range of parameters in which a state of cavity modes with poissonian or sub-poissonian (non-classical) statistics can be built up within the microcavity. Depending on the relative values of pumping and rate of stimulated emission, either one or two peaks close to the excitation energy of the dot and/or to the natural frequency of the cavity are observed in the emission spectrum. The physics behind these results is discussed.
Theoretical study of GaAs-based quantum dot lasers and microcavity light emitting diodes
2004
If the motion of a charge carrier in a solid is confined in a layer of a thickness of the order of the carrier's de Broglie wavelength, the energy spectrum of that charge carrier will become discrete. This size quantization effect was first applied in 1976 to improve laser performance [1]. For QDs with dimensions in the order of tens of nm, the three-dimensional confinement of charge carriers leads to discrete energy levels for electrons and holes, and QD lasers operating on these discrete levels exhibit new phenomena when compared to planar ...
A multiexcitonic quantum dot in an optical microcavity
Physica E: Low-dimensional Systems and Nanostructures, 2006
We theoretically study the coupled modes of a medium-size quantum dot, which may confine a maximum of ten electron-hole pairs, and a single photonic mode of an optical microcavity. Groundstate and excitation energies, exciton-photon mixing in the wave functions and the emission of light from the microcavity are computed as functions of the pair-photon coupling strength, photon detuning, and polariton number.
Emission characteristics of quantum dots in planar microcavities
Physical Review B, 2006
The emission properties of single quantum dots in planar microcavities are studied experimentally and theoretically. Fivefold Enhanced spontaneous emission outside the microcavity is found for dots in resonance with the cavity mode, relative to detuned dots, while their radiative lifetime is only marginally decreased. Using high power excitation we obtain the in-plane cavity dispersion. Near field images of the emission show spatial distributions of several microns for resonant dots, which decrease in size with the detuning from resonance. These experimental findings are explained using a simple and intuitive model.
Collective effects in emission of quantum dots strongly coupled to a microcavity photon
2012
A theory of non-linear emission of quantum dot ensembles coupled to the optical mode of the microcavity is presented. Numerical results are compared with analytical approaches. The effects of exciton-exciton interaction within the quantum dots and with the reservoir formed by nonresonant pumping are considered. It is demonstrated, that the nonlinearity due to the interaction strongly affects the shape of the emission spectra. The collective superradiant mode of the excitons is shown to be stable against the non-linear effects.
Exciton-photon strong-coupling regime for a single quantum dot embedded in a microcavity
Physical Review Letters, 2005
We report on the observation of the strong coupling regime between a single GaAs quantum dot and a microdisk optical mode. Photoluminescence is performed at various temperatures to tune the quantum dot exciton with respect to the optical mode. At resonance, we observe an anticrossing, signature of the strong coupling regime with a well resolved doublet. The Vacuum Rabi splitting amounts to 400 µeV and is twice as large as the individual linewidths.
Exciton photon strong-coupling regime for a single quantum dot in a microcavity
2004
We report on the observation of the strong coupling regime between a single GaAs quantum dot and a microdisk optical mode. Photoluminescence is performed at various temperatures to tune the quantum dot exciton with respect to the optical mode. At resonance, we observe an anticrossing, signature of the strong coupling regime with a well resolved doublet. The Vacuum Rabi splitting amounts to 400 μeV and is twice as large as the individual linewidths.
Cavity versus dot emission in strongly coupled quantum dots-cavity systems
2011
We discuss the spectral lineshapes of N quantum dots in strong coupling with the single mode of a microcavity. Nontrivial features are brought by detuning the emitters or probing the direct exciton emission spectrum. We describe dark states, quantum nonlinearities, emission dips and interferences and show how these various effects may coexist, giving rise to highly peculiar lineshapes.