Effective cavity pumping from weakly coupled quantum dots

We derive the effective cavity pumping and decay rates for the master equation of a quantum dot-microcavity system in presence of $N$ weakly coupled dots. We show that the in-flow of photons is not linked to the out-flow by thermal equilibrium relationships.Comment: 6 pages, 1 figure, PLMCN10 conference proceeding

Joint subnatural-linewidth and single-photon emission from resonance fluorescence

Resonance fluorescence—the light emitted when exciting resonantly a two-level system—is a popular quantum source as it seems to inherit its spectral properties from the driving laser and its statistical properties from the two-level system, thus providing a subnatural-linewidth single-photon source (SPS). However, these two qualities do not actually coexist in resonance fluorescence, since an optical target detecting these antibunched photons will either be spectrally broad itself and not benefit from the spectrally narrow source, or match spectrally with the source but in this case the antibunching will be spoiled. We first explain this failure through a decomposition of the field-emission and how this gets affected by frequency resolution. We then show how to restore the sought joint subnatural linewidth and antibunched properties, by interfering the resonance fluorescence output with a coherent beam. We finally discuss how the signal that is eventually generated in this way features a new type of quantum correlations, with a plateau of antibunching which suppresses much more strongly close photon pairs. This introduces a new concept of perfect SPS

Many-body physics of a quantum fluid of exciton-polaritons in a semiconductor microcavity

Some recent results concerning nonlinear optics in semiconductor microcavities are reviewed from the point of view of the many-body physics of an interacting photon gas. Analogies with systems of cold atoms at thermal equilibrium are drawn, and the peculiar behaviours due to the non-equilibrium regime pointed out. The richness of the predicted behaviours shows the potentialities of optical systems for the study of the physics of quantum fluids.Comment: Proceedings of QFS2006 conference to appear on JLT

Coherence dynamics in microcavities and polariton lasers

We study theoretically the second-order coherence g(2)(0) of light emitted by polariton lasers, i.e., devices based on stimulated relaxation and condensation of exciton–polaritons in microcavities. We solve kinetic equations for the polaritons in different approximations and show that (i) the coherence introduced into the polariton condensate by an external source can be conserved by the system over a macroscopically long time, and (ii) if the total number of polaritons is fixed by the excitation conditions, the correlations between the populations of the ground and excited polariton states can also result in the spontaneous buildup of second-order coherence in the polariton condensate. Both results are obtained neglecting polariton–polariton interactions in the condensate

Effects of Bose-Einstein condensation of exciton polaritons in microcavities on the polarization of emitted light

It is shown theoretically that Bose condensation of spin-degenerated exciton polaritons results in spontaneous buildup of the linear polarization in emission spectra of semiconductor microcavities and therefore that linear polarization is a good order parameter for the polariton Bose condensation under unpolarized pumping. If spin degeneracy is lifted, an elliptically polarized light is emitted by the polariton condensate. The main axis of the ellipse rotates in time due to self-induced Larmor precession of the polariton condensate pseudospin. The polarization decay time is governed by the dephasing induced by the polariton-polariton interaction and is strongly dependent on the statistics of the condensed state. If the elliptical polarization preexists in the system as a result of pumping, the lifetime of the linear part of the polarization is also extremely sensitive to the degree of circular polarization induced in the system by pumping. This decay time can be used to measure the coherence degree of the condensate as a function of the polarization of the emitted light, as opposed to more conventional but harder particle counting experiments of the Hanbury Brown-Twiss type

Polariton laser: thermodynamics and quantum kinetic theory

Cavity exciton–polaritons are considered to be two-dimensional weakly interacting true bosons. We analyse their thermodynamic properties and show that they can exhibit local condensation or Kosterlitz–Thouless phase transition towards superfluidity, so that polariton lasing can be achieved. The dynamical evolution of the condensate in a non-resonantly pumped cavity is described by a quantum kinetic formalism. The distribution function of polaritons is described by a semi-classical Boltzmann equation. A master equation for the ground-state density matrix is derived in the framework of the Born–Markov approximation. The dynamics of the ground-state population and its coherence are deduced

The long-run diversification attributes of commercial property

Bosonic cascades formed by lattices of equidistant energy levels sustaining radiative transitions between nearest layers represent a unique system to study correlated optical phenomena. We show how the light emitted by condensates in the visible range introduces a new regime of emission for cascade systems. Namely, the quantum statistics of bosonic cascades exhibits superbunching plateaus. This demonstrates further potentialities of bosonic cascade lasers for the engineering of correlated properties of light useful for imaging applications

Ultrafast Control and Rabi Oscillations of Polaritons

We report the experimental observation and control of space and time-resolved light-matter Rabi oscillations in a microcavity. Our setup precision and the system coherence are so high that coherent control can be implemented with amplification or switching off of the oscillations and even erasing of the polariton density by optical pulses. The data are reproduced by a quantum optical model with excellent accuracy, providing new insights on the key components that rule the polariton dynamics