Demonstration of a structured space–time wave packet having tailored range-dependent rotation motions

Space-time wave packets (STWPs) have gained interest for their dynamic varying properties. One previously demonstrated phenomenon is the dynamic motion resulting from the coherent combination of multiple frequency comb lines. However, the temporal dynamic patterns exhibit consistent characteristics along the longitudinal distance, leading to the reproduction of similar spatiotemporal phenomena at various distances, with a time delay induced by propagation. In this paper, we experimentally demonstrate the generation of a longitudinally controllable STWP with distinct dynamic transverse azimuthal rotations along its propagation distance. Our experimental measurements show a generated packet that rotates counterclockwise with a 4.8-ps period at 0.05 m and clockwise with a 2.4-ps period at 0.15 m.