Compact device for the generation of toroidal spatiotemporal optical vortices

Due to the unique spatiotemporal coupling characteristics in phase, spatiotemporal optical vortices have attracted extensive attention. Toroidal vortices, as high-dimensional spatiotemporal optical vortices, have become a research hotspot in recent years due to their unique topological structures. In this paper, we propose an asymmetric grating structure for the generation of optical toroidal vortices in a compact way. A cylindrical vector wave packet is transformed by the structure into a transmitted toroidal vortex pulse. Such a compact toroidal vortex generator may find applications in optical topology and high-dimensional optical communications.