Managing the flow of liquid light

Strongly coupled light-matter systems can carry information over long distances and realize low threshold polariton lasing, condensation and superfluidity. These systems are highly non-equilibrium in nature, so constant nonzero fluxes manifest themselves even at the steady state and set by a complicated interplay between nonlinearity, dispersion, pumping, dissipation and interactions between the various constituents of the system. Predicting the flow velocities even for a simple drive configuration has been challenging and no analytical spatially nonuniform solutions to the system were previously known. Based on the mean-field governing equations of lasers or polariton condensates, we develop a theoretical approach for engineering and controlling the velocity profiles by manipulating the spatial pumping and dissipation in the system. We present analytically exact pumping and dissipation profiles that lead to a large variety of spatially periodic density and velocity profiles. Our approach opens the way to the controllable implementation of laser or polariton flows for ultra-fast information processing and integrated circuits.