title: Spontaneous coherent phase transition of polaritons in CdTe microcavities.
abstract: We report on evidence for polariton condensation out of a reservoir of incoherent polaritons. Polariton population and first-order coherence are investigated by spectroscopic imaging of the far-field emission of a CdTe-based microcavity under nonresonant pumping. With increasing pumping power, stimulated emission with thresholdlike behavior and spectral narrowing is observed in the strong exciton-photon coupling regime. We show that it comes from a narrow ring in k space, exhibiting enhanced spatial and angular coherence at the stimulation onset.
authors.affiliation: CEA-CNRS-UJF group Nanophysique et semiconducteurs, Laboratoire de Spectrométrie Physique (CNRS UMR5588), Université J. Fourier-Grenoble, BP87, 38402 St Martin d'Hères, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Richard
authors.forename: Jacek
authors.initials: J
authors.lastname: Kasprzak
authors.forename: Robert
authors.initials: R
authors.lastname: Romestain
authors.forename: Régis
authors.initials: R
authors.lastname: André
authors.forename: Le Si
authors.initials: le S
authors.lastname: Dang