Researchers have developed a new class of integrated photonic devices — ‘leaky-wave metasurfaces’ — that convert light initially confined in an optical waveguide to an arbitrary optical pattern in free space. These are the first to demonstrate simultaneous control of all four optical degrees of freedom. Because they’re so thin, transparent, and compatible with photonic integrated circuits, they can be used to improve optical displays, LIDAR, optical communications, and quantum optics.