Fig. 3

Synthesized spatiotemporal vortex burst with time-varying T-OAM from ℓ = −3 to +3. a Measured iso-intensity profile of the spatiotemporal vortex burst in the space-time domain, which has a ~20 ps temporal length and a 2.8 ps temporal pitch. The isovalue is set to 8.5% of the peak intensity. The red and blue color denotes the negative and positive ℓ respectively. b Retrieved phase distribution in the meridional plane. c T-OAM modal analysis of the synthesized spatiotemporal vortex bursts, exhibiting time-varying T-OAMs with high mode purity (Supplementary Fig. S3), where \({r}_{{\rm{norm}}}=\sqrt{{\left(T-{t}_{0}\right)}^{2}/{w}_{t}^{2}+{(X-{x}_{0})}^{2}/{w}_{x}^{2}}\) is a normalized spatiotemporal polar radius (Supplementary Note 3). d Measured temporal/spatial radius (\({w}_{t}\) and \({w}_{x}\)) as a function of ℓ (\({t}_{0}\)), showing a spatiotemporal angular deceleration and acceleration along time, indicating an angular deceleration/acceleration on the space-time plane