Ultra-low threshold polariton condensation
  We demonstrate condensation of microcavity polaritons with a very sharp threshold occuring at two orders of magnitude lower pump intensity than previous demonstrations of condensation. The long cavity-lifetime and trapping and pumping geometries are crucial to the realization of this low threshold. Polariton condensation, or "polariton lasing" has long been proposed as a promising source of coherent light at lower threshold than traditional lasing, and these results suggest methods to bring this threshold even lower. 
Mark Steger, Brian Fluegel, Kirstin Alberi, Angelo Mascarenhas, David   W. Snoke, Loren N. Pfeiffer, Ken West
physics.optics cond-mat.mes-hall cond-mat.quant-gas