Ignition and formation dynamics of a polariton condensate on a   semiconductor microcavity pillar
  We present an experimental study on the ignition and decay of a polariton optical parametric oscillator (OPO) in a semiconductor microcavity pillar. The combination of a continuous wave laser pump, under quasi-phase matching conditions, and a non-resonant, 2 ps-long pulse probe allows us to obtain the full dynamics of the system. The arrival of the probe induces a blue-shift in the polariton emission, bringing the OPO process into resonance with the pump, which triggers the OPO-process. We time-resolve the polariton OPO signal emission for more than 1 nanosecond in both real and momentum-space. We fully characterize the emission of the OPO signal with spectral tomography techniques. Our interpretations are backed up by theoretical simulations based on the 2D coupled Gross-Pitaevskii equation for excitons and photons. 
C. Ant\'on, D. Solnyshkov, G. Tosi, M. D. Mart\'in, Z. Hatzopoulos, G.   Deligeorgis, P.G. Savvidis, G. Malpuech, and L. Vi\~na
cond-mat.mes-hall