Line integral compressed ultrafast photography for large time-scale measurements.

Compressed ultrafast photography (CUP) has attracted significant attention in the field of ultrafast optical imaging but is inherently constrained by a trade-off between sequence depth and spatial resolution. To address this limitation, we present a novel, to the best of our knowledge, system called spatial line integral CUP (LI-CUP). LI-CUP utilizes a cylindrical lens to compress each encoded time-slice frame into a spatial line, which is then recorded by a streak camera with a narrow slit. This approach transforms temporal compression into spatial compression, effectively decoupling the data compression rate from the imaging sequence depth. A deep unfolding algorithm is employed to ensure accurate reconstruction, and simulations confirm the validity of both the physical model and the algorithm. Experimental results demonstrate that the system can capture over one thousand time-slice frames of laser ablation in a single acquisition. This method significantly expands the capabilities of CUP, enabling measurements over larger time scales.