An imaging technique has been developed that can record non-repetitive ultrafast phenomena without strobe or flash illumination. The approach could find applications in biomedicine and security technologies. See Letter p.74
With the advent of fast electronic imaging sensors in the late 1960s, ultrafast photography became possible. Events even faster than a nanosecond can be captured with a streak camera — a device that records a single extended frame rather than a sequence of frames. However, this technique is inherently one-dimensional: to capture a two-dimensional image, the camera needs to scan the scene stepwise, requiring the event to be repetitive. Gao et al. now demonstrate a technique based on compressed imaging with a streak camera that can video record non-repetitive transient events in two dimensions at 100 billion frames per second, a temporal resolution down to tens of picoseconds. To demonstrate the potential of the technique, dubbed compressed ultrafast photography or CUP, the authors demonstrate ultra-fast imaging of laser pulses being reflected and refracted, and of photons racing in two media, as well as apparent faster-than-light propagation of non-information. It should be possible to couple CUP to anything from microscopes to telescopes.