MIT News 
Wednesday, March 21, 2012
In December, MIT Media Lab researchers caused a stir  by releasing a slow-motion video  of a burst of light traveling the length of a plastic bottle. But the experimental setup that enabled that video was designed for a much different application: a camera that can see around corners.
In a paper appearing this week in the journal Nature Communications, the researchers describe using their system to produce recognizable 3-D images of a wooden figurine and of foam cutouts outside their camera’s line of sight. The research could ultimately lead to imaging systems that allow emergency responders to evaluate dangerous environments or vehicle navigation systems that can negotiate blind turns, among other applications.
The principle behind the system is essentially that of the periscope. But instead of using angled mirrors to redirect light, the system uses ordinary walls, doors or floors — surfaces that aren’t generally thought of as reflective.
The system exploits a device called a femtosecond laser, which emits bursts of light so short that their duration is measured in quadrillionths of a second.
Full story here.