Time cloak used to hide messages in laser light

A “time cloak” that conceals events rather than objects can hide secret messages through a trick of light, making information invisible to all but the intended recipient.

Like an invisibility cloak that makes something disappear in plain sight, a time cloak makes an event disappear in time. It works by manipulating light traveling along an optical fibre.

Imagine a row of cars speeding along a road slowing down in concert to create brief paths for pedestrians to safely cross. When the cars that let the pedestrians cross ahead of them speed up and re-join the rest of the traffic, no one can tell there was ever a gap in the flow – the pedestrians’ presence has been cloaked.

In the same way, photons’ paths can be tweaked to create brief gaps where information can safely hide.

Last year, a team at Purdue University in Indiana built a cloak that could transfer hidden data at 1.5 gigabits a second, fast enough to make it theoretically useful for real communication. The only thing was….

By Aviva Rutkin – New Scientist –