Polygonal Spatiotemporal Optical Vortices Wavepackets with Prescribed Vortex Structure
Optical vortices carrying orbital angular momentum offer additional degrees of freedom. According to the orientation of orbital angular momentum, optical vortices can be classified into spatial optical vortex beam carrying longitudinalorbital angular momentum and spatiotemporal optical vortices carrying transverse orbital angular momentum. As an emerging subset of optical vortices, polygonal optical vortices provide a unique platform for a wide range of frontier applications by introducing a new degree of freedom in the form of a customizable intensity structure. In the spatial domain, polygonal spatial optical vortex beam carrying longitudinal orbital angular momentum have already demonstrated great potential in optical manipulation and two-photon lithography. However, polygonal spatiotemporal optical vortex wavepackets contain multiple sub spatiotemporal optical vortices carrying transverse orbital angular momentum remains unrealized to date. In this work, we theoretically propose and experimentally demonstrate polygonal spatiotemporal optical vortices wavepackets embedded with prescribed vortex structures. Within the structure, a prescribed number of sub spatiotemporal optical vortices carrying transverse orbital angular momentum is set along a designed polygonal spatiotemporal trajectory. Using the spatiotemporal holographic shaping approach, we generate polygonal perfect spatiotemporal optical vortex wavepacket and use the combination of multiple polygonal perfect spatiotemporal optical vortex wavepacket to form polygonal spatiotemporal optical vortex wavepacket with the prescribed vortex structure. A full control over multiple key properties of the polygonal spatiotemporal optical vortex wavepackets such as the geometry, number of phase singularities, and spatiotemporal distribution of sub spatiotemporal optical vortices is also achieved.