We observe spontaneously driven non-ground state polariton condensation in GaAs pillar microcavities under non-resonant optical excitation. We identify a regime where the interplay of exciton-exciton and pair polariton scattering can lead to mode switching from non-ground state to ground state polariton condensation. A simple kinematic model satisfactorily describes the observed mode switching as each of the above scattering mechanisms becomes prevalent at different carrier densities.
@article{arxiv.0907.3424,
title = {Spontaneous non-ground state polariton condensation in pillar microcavities},
author = {M. Maragkou and A. J. D. Grundy and E. Wertz and A. Lemaitre and I. Sagnes and P. Senellart and J. Bloch and P. G. Lagoudakis},
journal= {arXiv preprint arXiv:0907.3424},
year = {2015}
}