Single-shot 8-frame direct imaging with an effective frame rate up to 40 Tfps and a two-dimensional...

Compared with computational imaging, direct imaging is still a concern since it provides more intuitive and reliable spatiotemporal information of the target. The paper presents a single-shot ultrafast framing direct imaging based on polarization-spatial-encoding via non-collinear optical parametric amplification (OPA) with remarkable imaging seed and spatiotemporal resolutions. Here, a 2 × 4 architecture is designed for eight optical parametric amplifiers to get eight frames by polarization splitting. This architecture effectively suppresses signal depolarization and diffraction effects, particularly mitigating nonlinear effects during pump propagation, thus enhancing imaging quality compared with a 1 × 8 design. Targeted with laser-induced air plasma, our experiments verify that the single-shot imaging system has carried out 8-frame direct imaging by 25 fs temporal resolution, 40 trillion frames per second (Tfps) effective frame rate, and beyond 25.6 lp/mm spatial resolution over a 10 × 10 mm² field-of-view. The experimental results also show the capture of richer spatiotemporal details of air plasma in the early stage (0∼3.6 ps) after excitation. The temporal window can be flexibly expanded by changing the frame interval. This work provides a powerful tool for accurately understanding dynamic processes on the femtosecond to picosecond scale for non-repeatable or random dynamic scenarios.