Single-shot real-time imaging of ultrafast light springs

Light springs (LSs) have played essential roles in particle rotation and manipulation, optical super-resolution imaging, and optical information coding. In related research areas, it is important to accurately measure spatiotemporal information on LSs to understand and analyze their applications. However, there is no experimental method that can accurately detect the drastic spatial evolution of ultrafast LSs to date. Therefore, in this study, we propose a compressed ultrafast photography (CUP) technique to observe LSs in spatial and temporal dimensions with a snapshot. Using our home-built CUP system, we successfully capture spatiotemporal information on picosecond LSs with two and four petals, involving spatial structure and rotation velocity; furthermore, the experimental measurements are in good agreement with theoretical simulations. This study provides a novel visualization method for specifically measuring the spatial structure and temporal evolution of LSs, thus establishing a new idea for accurately characterizing spatiotemporal information on complex ultrafast laser fields.