Quantum statistics of polariton parametric interactions

EPL (Europhysics Letters), 2009

We show theoretically that polariton pairs with a high degree of polarization entanglement can be produced through parametric scattering. We demonstrate that it can emerge in coincidence experiments, even at low excitation densities where the dynamics is dominated by incoherent photoluminesce. Our analysis is based on a microscopic quantum statistical approach that treats coherent and incoherent processes on an equal footing, thus allowing for a quantitative assessment of the amount of entanglement under realistic experimental conditions. This result puts forward the robustness of pair correlations in solid-state devices, even when noise dominates one-body correlations.

2016

Polaritons are quasi-particles originating from the coupling of light with matter that demonstrated quantum phenomena at the many-particle mesoscopic level, such as BEC and superfluidity. A highly sought and long-time missing feature of polaritons is a genuine quantum manifestation of their dynamics at the single-particle level. Although they are conceptually perceived as entangled states and theoretical proposals abound for an explicit manifestation of their single-particle properties, so far their behaviour has remained fully accountable for by classical and mean-field theories. In this Article, we report the first experimental demonstration of a genuinely-quantum manifestation of microcavity polaritons, by swapping, in a two-photon entangled state generated by parametric down-conversion, a photon for a polariton. Furthermore, we show how single polaritons are affected by polariton-polariton interactions in a propaedeutic demonstration of their qualities for quantum information ap...

Physical Review Letters, 2005

We present an experiment that probes polariton quantum correlations by exploiting quantum complementarity. Specifically, we find that polaritons in two distinct idler-modes interfere if and only if they share the same signal-mode so that "which-way" information cannot be gathered. The experimental results prove the existence of polariton pair correlations that store the "which-way" information. This interpretation is confirmed by a theoretical analysis of the measured interference visibility in terms of quantum Langevin equations.

arXiv: Mesoscale and Nanoscale Physics, 2016

Polaritons are quasi-particles originating from the coupling of light with matter and that demonstrated quantum phenomena at the many-particle mesoscopic level, such as BEC and superuidity. A highly sought and long-time missing feature of polaritons is a genuine quantum manifestation of their dynamics at the single-particle level. Although they are conceptually perceived as entangled states and theoretical proposals abound for an explicit manifestation of their single-particle properties, so far their behaviour remained fully accountable for by classical and mean-field theories. In this Article, we report the first experimental demonstration of a genuinely-quantum manifestation of microcavity polaritons, by swapping the entanglement between a polariton and an external photon from a photon pair generated by parametric down-conversion. Moreover we demonstrate how interactions manifest at a single polariton level by perturbing the entangled state with a rarefied polariton condensate. O...

physica status solidi (c), 2004

We observe experimentally pronounced beats of the intensity of photoluminescence from a bottleneck region of a microcavity in the strong coupling regime. These beats are extremely sensitive to the pumping intensity and vanish for the weak pumping. We show theoretically that the process of polariton-polariton scattering leading to the mixing between bright and dark polariton states is responsible for this effect.

We report on spinor polariton interactions in GaAs based microcavity. This investigation is carried out by means of heterodyne polarized pump-probe spectroscopy. The results reveal the magnitude and the sign of interaction strength between polaritons with parallel and anti-parallel spins. We clearly show the dependence of the attractive and repulsive interaction constants with the cavity detuning. We evidence the strong influence of the biexciton resonance on the attractive interaction strength. Our modelization based on Gross-Pitaevskii equation reproduces the experimental observations. PACS numbers: 78.67. De, 71.36.+c Microcavity exciton polaritons are quasiparticles resulting from the strong coupling between excitons and photons . Polaritons exhibit mutual interactions coming from their excitonic content and light effective mass inherited from the photon. Moreover, the collected photons emitted from the cavity allow to read out the polaritons properties. As a matter of fact, a polariton fluid is an ideal tool for investigating quantum phenomena in solid-state systems. Polariton interactions in semiconductor microcavities play a crucial role in a wide variety of topics ranging from nonlinear optical effects, polariton superfluidity to Bose Einstein condensation. Their quantum coherence properties have been extensively investigated since the observation of polariton parametric processes [2-6]. First signs indicating spontaneous quantum degeneracy of polaritons appeared with the observation of stimulated emission under non-resonant excitation . In 2006, polariton Bose-Einstein condensation was demonstrated for the first time . Since then, many experiments have been performed to assess the superfluidity of polaritons, as well as the observation of full [10] and half quantized vortices, the demonstration of polariton flowing without scattering , and of solitons . The observation of the Bogoliubov excitations has been performed after initial indications of the linearization of the polariton dispersion .

arXiv (Cornell University), 2021

The polariton-polariton interaction strength is an important parameter for all kinds of applications using the nonlinear properties of polaritons, such as optical switching and single-photon blockade devices. In this paper, we review and compare the results of a series of experiments on polariton-polariton interactions in GaAs/Al x Ga 1−x As microcavity polariton structures, and present new theoretical analysis of these experiments. We show that not just the energy shift of the spectral lines, but also the results of measurements sensitive to the polariton scattering rate are important for the calibration of the interaction parameter at low excitation density. We find that when adjustments are made to correct for new understanding of the experiments, the value of the interaction parameter at low density is lower than previous reported, but still significantly higher than theoretically predicted.

physica status solidi (b), 2000

The spatial coherence of photoluminescence has been investigated in planar semiconductor (GaAs/AlAs) coupled l-cavities with InGaAs quantum wells in the active layer. The coherence length of the electromagnetic field of the microcavity polariton photoluminescence has been measured on the surface of the cavity, with the help of a metal grating fabricated on the cavity top mirror. The coherence length is found to be in the range of 5 to 10 mm, a few orders of magnitude larger than that of the quantum well exciton states. The calculations have shown that such a huge increase of the coherence length is due to the exciton±photon coupling in the microcavity.

Physical Review Letters, 2006

We study the optically-induced coupling between spins mediated by polaritons in a planar microcavity. In the strong coupling regime, the vacuum Rabi splitting introduces anisotropies in the spin coupling. Moreover, due to their photon-like mass, polaritons provide an extremely long spin coupling range. This suggests the realization of two-qubit all-optical quantum operations within tens of picoseconds with spins localized as far as hundreds of nanometers apart.

Solid State Communications, 2005

We report a new mechanism of non-linear coupling of optically active and dark crystal states. We observe experimentally pronounced beats of the intensity of photoluminescence from a bottleneck region of the exciton-polariton band in a microcavity in the strong coupling regime and at strong pumping. These beats are extremely sensitive to the pumping intensity and vanish for weak pumping. We show theoretically that coherent polariton-polariton scattering which leads to the mixing between bright and dark exciton states can be responsible for this effect.