SIOM reveals internal dynamics of spatiotemporal optical vortex strings
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Researchers at the Joint Laboratory for High Power Laser Physics at the Shanghai Institute of Optics and Fine Mechanics studied the internal dynamics of spatiotemporal optical vortex strings, uncovering phenomena such as spatiotemporal attraction and filamentation stretching. The results were published as "Probing Internal Dynamics of Spatiotemporal Optical Vortex Strings".
Shanghai Institute of Optics and Fine Mechanics Reports Progress on the Dynamics of Spatiotemporal Optical Vortices
Recently, a team from the Joint Laboratory for High-Power Laser Physics at the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, made progress in studying the dynamics of spatiotemporal optical vortices. The results, titled “Probing Internal Dynamics of Spatiotemporal Optical Vortex Strings: Spatiotemporal Attraction and Filament Stretching”, were published in Laser & Photonics Reviews.
Spatiotemporal optical vortices are light fields carrying phase singularities with spatiotemporal structure, showing great potential in high-dimensional information encoding and optical communications, attosecond physics, particle manipulation and other fields. However, a clear physical picture and direct experimental observation of the dynamical evolution of multiple spatiotemporal singularities within a single ultrashort pulse had been lacking. To address this, the team precisely controlled pulse dispersion and combined it with the independently proposed FIRST single-shot 3D measurement method. For the first time, within a single ultrafast spatiotemporal optical vortex wavepacket, they observed spatiotemporal attraction and spatiotemporal filament annihilation of the vortices, systematically revealing the intrinsic interaction mechanism of transverse orbital angular momentum singularities and verifying the universality of this dynamics for higher-order charges and asymmetric configurations.
Using this method, two basic types of dynamical behavior can be observed. The first is spatiotemporal attraction between like-sign vortices: three singularities with the same topological charge draw closer simultaneously in both space and time as the pulse is compressed temporally, producing the counterintuitive “spatiotemporal attraction” effect. The attraction strength is determined by the initial separation of the singularities — the closer they are, the stronger the interaction. This basic dynamical mechanism is likewise universal in higher-order or asymmetric scenarios. The second is spatiotemporal filamentation and annihilation of opposite-sign vortices: when vortices of opposite handedness are present in the wavepacket, the positive and negative singularities stretch each other into curved filamentary dark-field structures; the singularities annihilate, and the wavepacket splits into a two-lobed structure. Throughout the process the total topological charge is strictly conserved, and when the dispersion is scanned in reverse, the ring structure further splits into S-shaped double sheets.
All experimental observations in the study are in excellent agreement with theoretical predictions. The work also confirms that third-order dispersion, common in practical systems, does not alter the core dynamical behavior, demonstrating good robustness. This research not only confirms the cross-disciplinary commonality between optics and fluid mechanics in topological dynamics, but also opens up new possibilities for frontier applications such as precise control of ultrafast light fields, attosecond electron beam acceleration, and optical encrypted communications.
The related work was supported by the National Natural Science of China, the Chinese Academy of Sciences Pioneer Program, and the CAS Project for Young Teams in Basic Research, among other programs.
Figure1: Counterintuitive spatiotemporal attraction dynamics of spatiotemporal optical vortices with a (1 1 1) topological charge arrangement
Figure2: Spatiotemporal filamentation and annihilation dynamics of spatiotemporal optical vortices with a (1 -1 1) topological charge arrangement
X. Yao, X. Gao, P. Zhu, et al. “Probing Internal Dynamics of Spatiotemporal Optical Vortex Strings: Spatiotemporal Attraction and Filament Stretching.” Laser & Photonics Reviews (2026): e71918.
X. Yao, P. Zhu, Y. Yi, et al., “Single-Shot 3D Characterization of Spatiotemporal Wave Packets via a Spatiotemporal Wavefront Sensor (STWFS),” Optica 12, 12 (2025): 1884–1894.
Source: Shanghai Institute of Optics and Fine Mechanics (SIOM) · Research Updates · siom.cas.cn