Spatiotemporal circular airy optical vortices

Spatiotemporal optical vortices (STOVs), particularly those with high-order topological charges, are prone to singularity splitting during free-space propagation, resulting in limited propagation distances and modal instability and thereby constraining their potential applications. To improve the stability of STOV propagation in free space, here a circularly symmetric Airy phase is introduced within the spatial-frequency domain of STOV, leading to the development of a non-diffracting spatiotemporal vortex wave packet, referred to as spatiotemporal circular Airy optical vortex (STCAOV). Benefiting from its distinctive self-focusing properties, the STCAOV demonstrates an ultra-long stable propagation distance over 1000 mm in theory, representing at least a fivefold increase compared to STOV. Furthermore, its stable propagation distance and ring-shaped intensity radius can be flexibly controlled through the self-focusing effect. The experimental results exhibit significantly superior propagation stability compared with STOV. This advancement is expected to serve as a valuable solution for achieving stable propagation of various spatiotemporal optical fields.