Spatiotemporal optical wave packets with arbitrary trajectories

Spatiotemporal optical wave packets (STWPs) that are realized by spatiotemporal frequency coupling have the capacity to continuously control longitudinal group velocities from negative to superluminal. In this work, an inverse design algorithm based on the theory of stationary phase approximation is proposed to realize the design of arbitrarily variable trajectories for STWPs under non-paraxial conditions in free space. The central energy of the wave packet maintains almost constant intensity over long propagation distances, while the algorithm remains compatible with STWPs in complex dispersive systems.