Generation of robust spatiotemporal optical vortices with transverse orbital angular momentum beyond $10^2$

TL;DR

This paper demonstrates the theoretical and experimental generation of high-order spatiotemporal optical vortices that can stably carry transverse orbital angular momentum exceeding 100, opening new avenues for photon OAM applications.

Contribution

The work introduces a method to generate and control high-order transverse OAM in optical vortices beyond previous limits, with enhanced stability at higher orders.

Findings

Successfully generated transverse OAM beyond 100.

Enhanced stability of high-order STBOVs due to space-time coupling.

Controlled generation of any order STBOV using a 4f pulse shaper.

Abstract

Recently, photons have been observed to possess transverse orbital angular momentum (OAM); however, it is unclear as whether they can hold a transverse OAM higher than 1. Here, we theoretically and experimentally demonstrate that high-order spatiotemporal Bessel optical vortices (STBOVs) can stably carry transverse OAM even beyond $10^2$. Through the inverse design of the spiral phase, an STBOV of any order can be controllably generated using a 4f pulse shaper. In contrast to conventional longitudinal OAM, the vector direction of the transverse OAM can be distinguished by the unique time-symmetrical evolution of STBOVs. More interestingly, the stability of STBOVs improves with their increasing orders owing to enhanced space-time coupling, making these beams particularly suitable for the generation of ultra-high transverse OAM. Our work paves the way for further research and application of this unique OAM of photons.