Managing the flow of liquid light

Abstract

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 are set by a complicated interplay between nonlinearity, dispersion, pumping, dissipation and interactions between the various constituents of the system. Based on the mean-field governing equations of lasers or polariton condensates, we develop a method for engineering and controlling the velocity profiles by manipulating the system's spatial pumping and dissipation. We present analytically exact pumping and dissipation profiles that lead to a large variety of spatially periodic density and velocity profiles. Besides these, any physically relevant velocity profiles can be engineered by finding the stationary state of the conservative nonlinear Schrodinger equation in an external potential related to the velocity. Our approach opens the way to the controllable implementation of laser or polariton flows for ultra-fast information processing, integrated circuits, and analogue simulators.