Coherence properties and luminescence spectra of condensed polaritons in CdTe microcavities

M. H. Szymanska, F. M. Marchetti, Jonathan Mark James Keeling, P. B. Littlewood

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3 Citations (Scopus)

Abstract

We analyse the spatial and temporal coherence properties of a two-dimensional and finite sized polariton condensate with parameters tailored to the recent experiments which have shown spontaneous and thermal equilibrium polariton condensation in a CdTe microcavity [J. Kasprzak, M. Richard, S. Kundermann, A. Baas, P. Jeambrun, J.M.J. Keeling, F.M. Marchetti, M.H. Szymanska, R. Andre, J.L. Staehli, et al., Nature 443 (7110) (2006) 409]. We obtain a theoretical estimate of the thermal length, the lengthscale over which full coherence effectively exists (and beyond which power-law decay of correlations in a two-dimensional condensate occurs), of the order of 5 mu m. In addition, the exponential decay of temporal coherence predicted for a finite size system is consistent with that found in the experiment. From our analysis of the luminescence spectra of the polariton condensate, taking into account pumping and decay, we obtain a dispersionless region at small momenta of the order of 4 degrees. In addition, we determine the polariton linewidth as a function of the pump power. Finally, we discuss how, by increasing the exciton-photon detuning, it is in principle possible to move the threshold for condensation from a region of the phase diagram where polaritons can be described as a weakly interacting Bose gas to a region where instead the composite nature of polaritons becomes important. (C) 2007 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)364-370
Number of pages7
JournalSolid State Communications
Volume144
Issue number9
DOIs
Publication statusPublished - Dec 2007

Keywords

  • microcavity polaritons
  • quantum coherence
  • Bose-Einstein condensation
  • non-equilibrium
  • BOSE-EINSTEIN CONDENSATION
  • LASER

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