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Friday 10 October 2014

Scientists have created the most effective “invisibility cloak” so far, and you can make one for $100

Created by scientists at the University of Rochester in New York, the device can hide large objects from sight using cheap and readily available lenses.
“There’ve been many high tech approaches to cloaking and the basic idea behind these is to take light and have it pass around something as if it isn’t there, often using high-tech or exotic materials,” said John Howell, a professor of physics at the University of Rochester in a press release.
But while it works like an invisibility cloak, it looks more like something your optometrist would use to check your eyes - and when something is placed behind the layered lens, it disappears from view, leaving the background untouched.
“This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking, which works for transmitting rays in the visible spectrum,” graduate student Joseph Choi, who helped develop the technology with Howell, said in the release.
Previously, scientists had struggled to hide objects from varying angles, so they would be masked when you looked at them from straight on, but would be visible again when you moved your head. Now this new device has been used to cloak a hand, a face and a ruler from all angles. And the applications are pretty incredible - for example, a doctor could look through the lens and see the organs he was operating on below his hand. They could also let drivers see through their vehicle to their blind spot. Not to mention the fact that it can make you invisible, which is just freaking awesome.
The device can also be scaled up depending on the size of the lens, and would allow large objects to be cloaked. It also works for the whole visible spectrum of light, which means there are no limitations to what it can block.
It works by using four separate lenses with different focal lengths. By carefully calculating the distance between these lenses, Choi and Howell managed to bend the light around an object. They've submitted their results to the journal Optics Express, and the paper is also available onarXiv.org.
The team has now released instructions and equations that will help people build a similar device at home for around $100.

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