Optical induced vortices and persistent currents in polariton condensates

Observation of quantized vortices in non-equilibrium polariton condensates, suggesting parallelisms with conventional superfluids, have been reported either by spontaneous formation and pinning in the presence of disorder or by imprinting it onto the signal or idler of an optical parametric oscillator (OPO). Here we report the first observation of a polariton condensate receiving a quantized angular momentum by means of a short optical pulse and maintaining its rotation for a time much longer than the pulse duration, the polariton and coherence lifetimes. This observation shows a peculiar character of polariton condensates and reveals analogies with supercurrents in superconductors or persistent flow in condensates.