An ultrafast camera can create images of objects hidden behind a wall by capturing scattered laser light.

Ramesh Raskar at the Massachusetts Institute of Technology in Cambridge and his group fired a pulse of laser light at a wall on the far side of a hidden object (pictured, left), and recorded the time at which the scattered light — including the small fraction of photons that bounced off the object — reached their camera. The device records images every 2 picoseconds, allowing it to record the distance travelled by each photon with sub-millimetre precision. The team's algorithm then uses this information to reconstruct the image (right).

This ability to see around corners could be invaluable in dangerous or inaccessible locations, such as in highly contaminated areas or inside machinery with moving parts.

Nature Commun. 3, 745 (2012)