Peeking Through Keyholes With Lasers... well, yes and no.

An imaging technique that measures the path of a laser to build up a three-dimensional picture could now let spies map an entire room through a tiny hole.

In 2012, researchers used a laser to see around corners. The system worked by firing short laser pulses at a nearby wall, bouncing light around a corner to a hidden object, which then bounces some of it back to a camera next to the laser...

Now Chenfei Jin of the Harbin Institute of Technology in China and colleagues have taken this a step further. They used a laser set-up to measure the 3D shape and position of three cardboard letters, spelling HIT, through a 2 centimetre hole in a nearby wall...

The letters were coated in highly reflective material while the rest of the room was covered in black light-absorbing cloth, so the technique might not work as well in a real-world setting...

Guy Satat of the Massachusetts Institute of Technology says he likes the work, but points out that if the hole were easily accessible, it would be easier for would-be spies to simply put a camera up against the wall and take a photo of the room.
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