Collective effects in emission of quantum dots strongly coupled to a microcavity photon (original) (raw)
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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.
Cooperative exciton–photon dynamics of a linear chain of quantum dots in a perfect microcavity
Physica E: Low-dimensional Systems and Nanostructures, 2009
Cooperative exciton-photon dynamics of a linear chain consisting of closely spaced quantum dots has been studied numerically in the simplified Jaynes-Cummings model with dipole-dipole interaction and only nearest neighbor interactions. In the aggregate, quantum dots are assumed to be coupled with a single mode field of a perfect microcavity. In the chain, the transport of the excitation energy via resonance dipole-dipole interaction generates propagating exciton-waves which interfere with themselves in the mediation of photon field. We show that the absorption and emission of the field is inhibited or enhanced depending on system parameters and the excitation of specified quantum dots is also suppressed or enforced depending on dipole-dipole coupling constant.
Statistics of excitons in quantum dots and the resulting microcavity emission spectra
2005
A theoretical investigation is presented of the statistics of excitons in quantum dots (QDs) of different sizes. A formalism is developed to build the exciton creation operator in a dot from the single exciton wavefunction and it is shown how this operator evolves from purely fermionic, in case of a small QD, to purely bosonic, in case of large QDs. Nonlinear optical emission spectra of semiconductor microcavities containing single QDs are found to exhibit a peculiar multiplet structure which reduces to Mollow triplet and Rabi doublet in fermionic and bosonic limits, respectively.
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.
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.
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.
physica status solidi (c), 2005
We present an overview of the model we developed (F. P. Laussy et al.,) to describe strong coupling of light with excitons hosted by large quantum dots, where the number of excitons is eventually limited by Pauli blocking of the underlying electron-hole structure. We apply it to a limiting case not investigated before, where excitations are created in states analogous of Dicke states describing non-interacting distinguishable fermionic excitations coupled through the radiation field. The multiplet structures in the optical emission spectra which we obtain show, by comparison with our previous results, that they remain essentially the same independently of the model for small saturation numbers, while they acquire specificities of their own when the number of allowed excitons becomes large.
Physical Review B, 2006
A theoretical investigation is presented of the statistics of excitons in quantum dots ͑QDs͒ of different sizes. A formalism is developed to build the exciton creation operator in a dot from the single exciton wave function and it is shown how this operator evolves from purely fermionic, in the case of a small QD, to purely bosonic, in the case of large QDs. Nonlinear optical emission spectra of semiconductor microcavities containing single QDs are found to exhibit a peculiar multiplet structure which reduces to Mollow triplet and Rabi doublet in fermionic and bosonic limits, respectively. ͓a,a † ͔ = 1, ͑1͒
Collective modes of quantum dot ensembles in microcavities
Journal of Experimental and Theoretical Physics, 2009
Emission spectra of quantum dot arrays in zero-dimensional microcavities are studied theoretically, and it is shown that they are determined by the competition between the formation of the collective superradiant mode and inhomogeneous broadening. The random sources method for the calculation of photoluminescence spectra under a non-resonant pumping is developed, and a microscopic justification of the random sources method within a framework of the standard diagram technique is given. The emission spectra of a microcavity are analyzed with allowance for the spread of exciton states energies caused by an inhomogeneous distribution of quantum dots and a tunneling between them. It is demonstrated that in the case of a strong tunneling coupling the luminescence spectra are sensitive to the geometric positions of the dots, and the collective mode can, under certain conditions, be stabilized by the random tunnel junctions.
Optics Express, 2009
A strongly coupled quantum dot-micropillar cavity system is studied under variation of the excitation power. The characteristic double peak spectral shape of the emission with a vacuum Rabi splitting of 85 μeV at low excitation transforms gradually into a single broad emission peak when the excitation power is increased. Modelling the experimental data by a recently published formalism [Laussy et al., Phys. Rev. Lett. 101, 083601 (2008)] yields a transition from strong coupling towards weak coupling which is mainly attributed to an excitation power driven decrease of the exciton-photon coupling constant.