Manni, F.Lagoudakis, K. G.André, R.Wouters, M.Deveaud, B.2012-10-152012-10-152012-10-15201210.1103/PhysRevLett.109.150409https://infoscience.epfl.ch/handle/20.500.14299/86151WOS:000309658300003We perform quantum tomography on one-dimensional polariton condensates, spontaneously occurring in linear disorder valleys in a CdTe planar microcavity sample. By the use of optical interferometric techniques, we determine the first-order coherence function and the amplitude and phase of the order parameter of the condensate, providing a full reconstruction of the single particle density matrix for the polariton system. The experimental data are used as input to theoretically test the consistency of the Penrose-Onsager criterion for Bose-Einstein condensation in the framework of nonequilibrium polariton condensates. The results confirm the pertinence and validity of the criterion for a nonequilibrium condensed gas.bose-einstein condensation polariton opticstext::journal::journal article::research article