Time cloak Pentagon Cornell

Time cloak Pentagon Cornell

Time cloak Pentagon Cornell - 'Time cloak' invented, Scientists at Cornell University say they've created a "time cloak" device that can not only render an object invisible, but also make an entire event like it never happened. Military leaders at the Pentagon reportedly want to get their hands on it.

PENTAGON-supported physicists say they have devised a "time cloak" that briefly makes an event undetectable.

The laboratory device manipulates the flow of light in such a way that for the merest fraction of a second an event cannot be seen, according to a paper published in the science journal Nature.

It adds to experimental work in creating next-generation camouflage - a so-called invisibility cloak in which specific colours cannot be perceived by the human eye.

"Our results represent a significant step towards obtaining a complete spatio-temporal cloaking device," says the study, headed by Moti Fridman of Cornell University in New York.

The breakthrough exploits the fact that frequencies of light move at fractionally different speeds.

The so-called temporal cloak starts with a beam of green light that is passed down a fibre-optic cable.
The beam goes through a two-way lens that splits it into two frequencies - blueish light that travels relatively fast, and reddish light that is slower.

The tiny difference in speed is then accentuated by placing a transparent obstacle in front of the two beams.

Eventually a time gap opens up between the red and blue beams as they travel through the optical fibre.

The gap is tiny - just 50 picoseconds, or 50 millionths of a millionth of a second.

But it is just long enough to squeeze in a pulse of laser at a different frequency from the light passing through the system.