Photon lasing in GaAs microcavity: Similarities with a polariton condensate

We study experimentally the lasing regime of a GaAs based microcavity sample under strong optical pumping. The very same sample exhibits the strong coupling regime at low excitation power with a Rabi splitting as large as 15 meV. We show that some features which may be considered as experimental evidence of polariton Bose-Einstein condensation are also observed in the weak coupling regime when the cavity is behaving as a regular photon laser. In particular, the emission pattern in the lasing regime displays a sharp peak near the energy minimum followed by a Boltzmann distribution at higher energies.