Optical bistability in a GaAs based polariton diode
  We report on a new type of optical nonlinearity in a polariton p-i-n microcavity. Abrupt switching between the strong and weak coupling regime is induced by controlling the electric field within the cavity. As a consequence bistable cycles are observed for low optical powers (2-3 orders of magnitude less than for Kerr induced bistability). Signatures of switching fronts propagating through the whole 300 microns x 300 microns mesa surface are evidenced. 
Daniele Bajoni. Elizaveta Semenova, Aristide Lema\^itre, Sophie   Bouchoule, Esther Wertz, Pascale Senellart, Sylvain Barbay...