title: Coherence expansion and polariton condensate formation in a semiconductor microcavity.
abstract: The dynamics of the expansion of the first order spatial coherence g(1) for a polariton system in a high-Q GaAs microcavity was investigated on the basis of Young's double slit experiment under 3 ps pulse excitation at the conditions of polariton Bose-Einstein condensation. It was found that in the process of condensate formation the coherence expands with a constant velocity of about 10(8)  cm/s. The measured coherence is smaller than that in a thermal equilibrium system during the growth of condensate density and well exceeds it at the end of condensate decay. The onset of spatial coherence is governed by polariton relaxation while condensate amplitude and phase fluctuations are not suppressed.
authors.affiliation: P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991, Russia. belykh@lebedev.ru
authors.forename: V V
authors.initials: VV
authors.lastname: Belykh
authors.forename: N N
authors.initials: NN
authors.lastname: Sibeldin
authors.forename: V D
authors.initials: VD
authors.lastname: Kulakovskii
authors.forename: M M
authors.initials: MM
authors.lastname: Glazov
authors.forename: M A
authors.initials: MA
authors.lastname: Semina
authors.forename: C
authors.initials: C
authors.lastname: Schneider
authors.forename: S
authors.initials: S
authors.lastname: Höfling
authors.forename: M
authors.initials: M
authors.lastname: Kamp
authors.forename: A
authors.initials: A
authors.lastname: Forchel