Single‐Shot Reconfigurable Femtosecond Imaging of Ultrafast Optical Dynamics

Understanding ultrafast dynamics in the femtosecond timescale plays a pivotal role in fundamental research and technology innovation. Spatiotemporal observation of those events in real-time requires imaging speeds greater than 10¹² frames per second (fps), far beyond the fundamental speed limits of the ubiquitous semiconductor sensor technologies. In addition, a majority of femtosecond events are non-repeatable or difficult-to-repeat since they either work in a highly unstable nonlinear regime or require extreme or rare conditions to initiate. Therefore, the traditional pump-probe imaging approach fails since it heavily depends on precise event repetition. Single-shot ultrafast imaging emerges as the only solution; however, existing techniques cannot reach more than 15×10¹² fps, and they only record an insufficient number of frames. Compressed ultrafast spectral photography (CUSP) is proposed to overcome these limitations. Here, CUSP's full design space is explored by manipulating the ultrashort optical pulse in the active illumination. Via parameter optimization, an extraordinarily fast frame rate of 219 × 10¹² fps is achieved. This implementation of CUSP is also highly flexible, allowing various combinations of imaging speeds and numbers of frames (several hundred up to 1000) to be readily deployed in diverse scientific studies, such as laser-induced transient birefringence, self-focusing, and filaments in dielectric media.