Recently, Professor CAI Yangjian's team from the Center for Light Field Regulation and Application, School of Physics and Electronic Science, Shandong Normal University published a paper entitled "Spatiotemporal optical vortices with controllable" in the international top journal Nature Communications radial and azimuthal quantum numbers "research paper. Liu Xin, PhD candidate, is the first author of the paper. Professor CAI Yangjian and Professor Zhan Qiwen from University of Shanghai for Science and Technology are the corresponding authors of the paper.

The field of structured light field regulation opens up new ways to manipulate the complex interactions of light in space-time. As a fascinating branch of structured light, optical space-time vortices have received great attention and development in recent years. The explosion of research results in this field stems from the unique properties of the space-time vortex light: the phase singularities in the time domain and the transverse photon orbital angular momentum. However, current research focuses on space-time optical vortices based on spatiotemporal Gaussian wave packets and with only a single controllable angular index of degrees of freedom in the spatiotemporal domain. In addition, the ability to synthesize and manipulate spacetime vortices and structured light fields with more complex spacetime topologies remains a challenge. In this work, the generation and mode conversion of space-time wave packets with multiple degrees of freedom are realized for the first time by using the space-time spectral polymodulation technique of ultrafast femtosecond laser. The generated space-time Laguerre and Hermitetic wave packets are orthogonal complete as the solutions of the wave equation, which lays a foundation for the future space-time structured light field regulation.

The above research has been funded by the national key research and development project, the National Natural Science Foundation major project, the National Natural Science Foundation major research project, etc.