When I was a kid, there was a periscope you could make out of a cardboard tube and two small hand mirrors to see around corners. Now there’s a video camera system that can do the same.
Camera Can See Around Corners and Femtosecond Camera Sees Around Corners articles tell that Scientists at the Massachusetts Institute of Technology in Cambridge have created a camera that is able to record images of objects hidden behind walls. The video system, called Cornar, was created by researchers at the Massachusetts Institute of Technology’s Media Lab. It can look beyond the line of sight, as well as peer around corners.
Conar is based on a ultra-fast camera sensor and a femtosecond laser. Conar works by firing a pulse of laser light at a wall on the far side of the hidden scene, and record the time at which the scattered light reaches a camera. Bursts of light generated by the laser reflect off of multiple surfaces and reconstruct a 3D image. The camera captures this time-of-flight information and uses it to reconstruct an image of the hidden object (abstract). Photons bounce off the wall onto the hidden object and back to the wall, scattering each time, before a small fraction eventually reaches the camera, each at a slightly different time.
How to see around corners article points to this nice video of Conar operation.
It seems that scattering is not the only way to bend light around corner. Light normally travels in straight lines, but physicists have known for several years that superimposing a pattern on a laser beam can make it bend. Self-bending light boomerangs could help surgeons article tells that self-beaming light beams are capable of turning a corner like a boomerang. They are darting around an optics laboratory in France. The team have bent beams just a few micrometres across by up to 60 degrees, using a device known as a spatial light modulator. The beam pattern is designed so that the individual light rays that make up the beam interfere with each other in a way that makes the beam curve. Dudley’s team has already used these bendy lasers to carve glass into curved shapes.