Second-harmonic generation of spatiotemporal optical vortices and conservation of orbital angular momentum

A spatiotemporal optical vortex (STOV) is an intrinsic optical orbital angular momentum (OAM) structure in which the OAM vector is orthogonal to the propagation direction [Optica 6, 1547 (2019)] and the optical phase circulates in space-time. Here, we experimentally and theoretically demonstrate the generation of the second harmonic of a STOV-carrying pulse along with the conservation of STOV-based OAM. Our experiments verify that photons can have intrinsic orbital angular momentum perpendicular to their propagation direction. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This study demonstrates the generation and conservation of spatiotemporal optical vortex (STOV) and verifies the existence of intrinsic orbital angular momentum of photons. The experiments show that photons can carry angular momentum perpendicular to their propagation direction.