Single-shot tomographic movies of evolving light-velocity objects

Tomography—cross-sectional imaging based on measuring radiation transmitted through an object along different directions—enables non-invasive imaging of hidden stationary objects, such as internal bodily organs, from their sequentially measured projections. Here we adapt tomographic methods to visualize—in one laser shot—the instantaneous structure and evolution of a laser-induced object propagating through a transparent Kerr medium. We reconstruct 'movies' of a laser pulse's diffraction, self-focusing and filamentation from phase 'streaks' imprinted onto probe pulses that cross the main pulse's path simultaneously at different angles. Multiple probes are generated and detected compactly and simply, making the system robust, easy to align and adaptable to many problems. Our technique could potentially visualize, for example, plasma wakefield accelerators, optical rogue waves or fast ignitor pulses, light-velocity objects, whose detailed space–time dynamics are known only through intensive computer simulations. Tomography enables the reconstruction of objects, and its application to moving objects uncovers otherwise hidden phenomena, particularly at light velocity. Li et al.present a tomographic method that can visualize evolving laser-induced structures in a single shot.