Microcavity polaritons are two-dimensional bosonic fluids with strong nonlinearities, composed of coupled photonic and electronic excitations. In their condensed form, they display quantum hydrodynamic features similar to atomic Bose–Einstein condensates, such as long-range coherence, superfluidity and quantized vorticity. Here we report the unique phenomenology that is observed when a pulse of light impacts the polariton vacuum: the fluid which is suddenly created does not splash but instead coheres into a very bright spot. The real-space collapse into a sharp peak is at odd with the repulsive interactions of polaritons and their positive mass, suggesting that an unconventional mechanism is at play. Our modelling devises a possible explanation in the self-trapping due to a local heating of the crystal lattice, that can be described as a collective polaron formed by a polariton condensate. These observations hint at the polariton fluid dynamics in conditions of extreme intensities and ultrafast times.
Dominici, L., Petrov, M., Matuszewski, M., Ballarini, D., De Giorgi, M., Colas, D., Cancellieri, E., Silva Fernández, B., Bramati, A., Gigli, G., Kavokin, A., Laussy, F., & Sanvitto, D. (2015). Real-space collapse of a polariton condensate. Nature Communications, 6, 8993. https://doi.org/10.1038/ncomms9993