Scientists' new time masker creates invisibility
SCIENCE
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In this 2011 illustration, provided by Cornell University, scientists demonstrate how they have have created, a new invisibility technique that doesn't just cloak an object _ like in Harry Potter books and movies _ but masks an entire event. It is a time masker that works by briefly bending the speed of light around an event. Cornell scientists explain what they are talking about in this 2011 illustration that shows that if this technique is ever scaled up an art thief can walk into a museum and steal a painting without setting of laser beam alarms or even showing up on surveillance cameras or your eyes. (AP Photo/Heather Deal, Cornell University) lessIn this 2011 illustration, provided by Cornell University, scientists demonstrate how they have have created, a new invisibility technique that doesn't just cloak an object _ like in Harry Potter books and ... morePhoto: Heather Deal, Associated Press
Washington --
It's one thing to make an object invisible, like Harry Potter's mythical cloak. But scientists have made an entire event impossible to see. They have invented a time masker.
Think of it as an art heist that takes place before your eyes and surveillance cameras. You don't see the thief strolling into the museum, taking the painting down or walking away, but he did. It's not just that the thief is invisible - his whole activity is.
What scientists at Cornell University did was on a much smaller scale, both in terms of events and time. It happened so quickly that it's not even a blink of an eye. Their time cloak lasts an incredibly tiny fraction of a fraction of a second. They hid an event for 40 trillionths of a second, according to a study appearing in Thursday's edition of the journal Nature.
We see events happening as light from them reaches our eyes. Usually it's a continuous flow of light. In the new research, however, scientists were able to interrupt that flow for just an instant.
Other newly created invisibility cloaks fashioned by scientists move the light beams away in the traditional three dimensions. The Cornell team alters not where the light flows but how fast it moves, changing in the dimension of time, not space.
They tinkered with the speed of beams of light in a way that would make it appear to surveillance cameras or laser security beams that an event, such as an art heist, isn't happening.
Another way to think of it is as if scientists edited or erased a split second of history. It's as if you are watching a movie with a scene inserted that you don't see or notice. It's there in the movie, but it's not something you saw, said study co-author Moti Fridman, a physics researcher at Cornell.
"You kind of create a hole in time where an event takes place," said study co-author Alexander Gaeta, director of Cornell's School of Applied and Engineering Physics. "You just don't know that anything ever happened."
This is all happening in beams of light that move too fast for the human eye to see. Using fiber optics, the hole in time is created as light moves along inside a fiber much thinner than a human hair.
The scientists shoot the beam of light out, and then with other beams, they create a time lens that splits the light into two different speed beams that create the effect of invisibility by being too fast or too slow. The whole work is a mess of fibers on a long table and almost looks like a pile of spaghetti, Fridman said.
It is the first time that scientists have been able to mask an event in time, a concept only first theorized by Martin McCall, a professor of theoretical optics at Imperial College in London. Fridman and others at Cornell, who had already been working on time lenses, decided to see if they could do what McCall envisioned.
It only took a few months, a blink of an eye in scientific research time.
"It is significant because it opens up a whole new realm to ideas involving invisibility," McCall said.