Single‐Shot Reconfigurable Femtosecond Imaging of Ultrafast Optical Dynamics

Abstract

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.

Tutorial on compressed ultrafast photography

“…In the future, transient perturbation in reflective index induced by a temporally modulated ultrashort laser pulse or molecular orientation could bring higher imaging speeds and circumvent image degradation. 151,170 Leveraging the advance in chirped pulse illumination, CUP systems using passive temporal shearing units have boosted the imaging speed to 3.85 × 10 12 fps, 121 70 × 10 12 fps, 57 219 × 10 12 fps, 198 and 256 × 10 12 fps. 63 The last value marks the fastest speed in single-shot optical imaging.…”

“…Leveraging the advance in chirped pulse illumination, CUP systems using passive temporal shearing units have boosted the imaging speed to 3.85×1012 fps, 121 70×1012 fps, 57 219×1012 fps, 198 and 256×1012 fps 63 . The last value marks the fastest speed in single-shot optical imaging.…”

Introducing the Special Issue Honoring Lihong V. Wang, Pioneer in Biomedical Optics

“…CUP represents a groundbreaking technique that transcends traditional limitations, allowing for unprecedented 2D imaging of transient events at an astonishing frame rate of 219 trillion frames per second. 24 , 25 What distinguishes the CUP technique from conventional approaches is its reliance on passive data acquisition, leveraging the camera’s inherent capabilities for temporal resolution rather than requiring active illumination. This unique attribute vastly broadened the scope of CUP applications, enabling imaging not only in transmitted light but also in fluorescence, bioluminescence, and chemiluminescence.…”

Design for Ultrafast Raster Photography with a Large Amount of Spatio-Temporal Information

“…To capture non-repetitive processes, various single-shot ultrafast imaging techniques have emerged, boasting frame rates of up to a trillion frames per second (Tfps). These include ultrafast compressed photography (CUP) [14][15][16][17][18][19] with passive detection and active detection-based photography [20,21], which leverage spatial multiplexing encoding [22] and division techniques such as space and are based on space division [23][24][25][26],…”