G. Nardin

Publications (7)7.37 Total impact

• Source

  Available from: Benoit Deveaud

  Article: Soliton instabilities and vortex street formation in a polariton quantum fluid.

  G Grosso, G Nardin, F Morier-Genoud, Y Léger, B Deveaud-Plédran
  [show abstract] [hide abstract]
  ABSTRACT: Exciton polaritons have been shown to be an optimal system in order to investigate the properties of bosonic quantum fluids. We report here on the observation of dark solitons in the wake of engineered circular obstacles and their decay into streets of quantized vortices. Our experiments provide a time-resolved access to the polariton phase and density, which allows for a quantitative study of instabilities of freely evolving polaritons. The decay of solitons is quantified and identified as an effect of disorder-induced transverse perturbations in the dissipative polariton gas.
  Physical Review Letters 12/2011; 107(24):245301. · 7.37 Impact Factor
• Source

  Available from: ArXiv

  Article: Soliton Instabilities and Vortex Streets Formation in a Polariton Quantum Fluid

  G. Grosso, G. Nardin, F. Morier-Genoud, Y Léger, B Deveaud-Plédran
  [show abstract] [hide abstract]
  ABSTRACT: Exciton-polaritons have been shown to be an optimal system in order to investigate the properties of bosonic quantum fluids. We report here on the observation of dark solitons in the wake of engineered circular obstacles and their decay into streets of quantized vortices. Our experiments provide a time-resolved access to the polariton phase and density, which allows for a quantitative study of instabilities of freely evolving polaritons. The decay of solitons is quantified and identified as an effect of disorder-induced transverse perturbations in the dissipative polariton gas.
  09/2011;
• Source

  Available from: Benoit Deveaud

  Article: Optical manipulation of the wave function of quasiparticles in a solid

  R. Cerna, D. Sarchi, T. K. Paraiso, G. Nardin, Y. Leger, M. Richard, B. Pietka, O. El Daif, F. Morier-Genoud, V. Savona, M. T. Portella-Oberli, B. Deveaud-Pledran
  [show abstract] [hide abstract]
  ABSTRACT: Polaritons in semiconductor microcavities are hybrid quasiparticles consisting of a superposition of photons and excitons. Due to the photon component, polaritons are characterized by a quantum coherence length in the several micron range. Owing to their exciton content, they display sizeable interactions, both mutual and with other electronic degrees of freedom. These unique features have produced striking matter wave phenomena, such as Bose-Einstein condensation, or parametric processes able to generate quantum entangled polariton states. Recently, several paradigms for spatial confinement of polaritons in semiconductor devices have been established. This opens the way to quantum devices in which polaritons can be used as a vector of quantum information. An essential element of each quantum device is the quantum state control. Here we demonstrate control of the wave function of confined polaritons, by means of tailored resonant optical excitation. By tuning the energy and momentum of the laser, we achieve precise control of the momentum pattern of the polariton wave function. A theoretical model supports unambiguously our observations.
  05/2009;
• Source

  Available from: Benoit Deveaud

  Article: Dynamics of long-range order in an exciton-polariton condensate

  G. Nardin, K. G. Lagoudakis, M. Wouters, M. Richard, A. Baas, R. Andre, Le Si Dang, B. Pietka, B. Deveaud-Pledran
  [show abstract] [hide abstract]
  ABSTRACT: We report on time resolved measurements of the first order spatial coherence in an exciton polariton Bose-Einstein condensate. Long range spatial coherence is found to set in right at the onset of stimulated scattering, on a picosecond time scale. The coherence reaches its maximum value after the population and decays slower, staying up to a few hundreds of picoseconds. This behavior can be qualitatively reproduced, using a stochastic classical field model describing interaction between the polariton condensate and the exciton reservoir within a disordered potential. Comment: 7 pages, 4 figures
  05/2009;
• Source

  Available from: Benoit Deveaud

  Article: Coherent optical control of the wave function of zero dimensional exciton polaritons

  R. Cerna, D. Sarchi, T. K. Paraïso, G. Nardin, Y Léger, M. Richard, B. Pietka, O. El Daif, F. Morier-Genoud, V. Savona, M. T. Portella-Oberli, B Deveaud-Plédran
  [show abstract] [hide abstract]
  ABSTRACT: Control of the wave function of confined microcavity polaritons is demonstrated experimentally and theoretically by means of tailored resonant optical excitation. Three dimensional confinement is achieved by etching mesas on top of the microcavity spacer layer. Resonant excitation with a continuous-wave laser locks the phase of the discrete polariton states to the phase of the laser. By tuning the energy and momentum of the laser, we achieve precise control of the momentum pattern of the polariton wave function. This is an efficient and direct way for quantum control of electronic excitations in a solid.
• Source

  Available from: Benoit Deveaud

  Article: Coherent oscillations between polariton vortex and anti-vortex states in an elliptical resonator

  G Nardin, Y Léger, B Pietka, F Morier-Genoud, B Deveaud-Plédran
  [show abstract] [hide abstract]
  ABSTRACT: In this experimental work, we optically excite the eigenmodes of an elliptical resonator in a semiconductor micro-cavity. Using a pulsed excitation, we create a superposition of eigenmodes, and image the time evolution of the coherent emission pattern. Oscillations between vortex and anti-vortex states are observed, and remarkably well described within the Poincaré sphere representation for an eigenmode containing an orbital angular momentum. A semiconductor quantum well is embedded in the microcavity structure. The system is operated in the strong light matter coupling regime, where the eigenmodes are hybrid half-photonic half-excitonic quasiparticles called exciton polaritons.
• Source

  Available from: Benoit Deveaud

  Article: Enhancement of microcavity polariton relaxation under confinement

  T. K. Paraïso, D. Sarchi, G. Nardin, R. Cerna, Y. Leger, B. Pietka, M. Richard, O. El Daïf, F. Morier-Genoud, V. Savona, B. Deveaud-Plédran
  [show abstract] [hide abstract]
  ABSTRACT: We experimentally investigate the relaxation of spatially confined microcavity polaritons. We measure the time- and energy-resolved photoluminescence under resonant excitation and in the low-density regime. In this way, we have access to the time evolution of the energy distribution of the polariton population. We show that, when one confined level is resonantly excited, after an initial transient, the population of the confined levels is thermally distributed. The reported efficiency of the relaxation process strongly depends on the confinement size. These experimental findings are well reproduced by a theoretical model accounting for the coupling between the confined states and a bath of acoustic phonons. Our results thus suggest that the phonon-mediated relaxation mechanisms are enhanced in the presence of spatial confinement.
  Phys. Rev. B. 79(4).