High-time-resolution and high-contrast spatiotemporal vortex measurement technology

This research focuses on the transmission characteristics of complex ultrafast spatiotemporal vortex beams. The core methodology involves Sum-frequency generation (SFG) imaging principles for time-resolved sampling of femtosecond light fields. This technique is combined with Mach-Zehnder interferometry, enabling the acquisition of high-resolution, high-contrast interference patterns, which are crucial for detailed analysis of spatiotemporal vortex characteristics. To quantitatively decode the complex information contained in these interference patterns, Fourier transform methods are employed. This computational approach allows for the simultaneous extraction of amplitude envelopes and precise phase distributions from the measured interference patterns, aiding in the reconstruction of the evolving spatiotemporal wavefront and the dynamics of phase singularity evolution. The results provide valuable insights into the dynamic behavior of phase singularities inherent in vortices, contributing to a deeper understanding of the evolution and properties of spatiotemporal vortices in the ultrafast regime. Our work not only presents a powerful tool for diagnosing complex spatiotemporal optical fields but also paves the way for advanced applications in ultrafast metrology, optical trapping, and quantum information processing utilizing time-domain structured light.