University of Rochester Scientists Create Harry Potter Invisibility Cloak

Harry Potter's 'invisibility cloak' cracked: University of Rochester scientists create masking device

By Allie Healy | ahealy@syracuse.com 

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on September 28, 2014

Who needs magic when you have science? Noted to match the powers of Harry Potter's "Cloak of Invisibility," a device created by University of Rochester scientists completely hides objects from view.

According to the University of Rochester Newscenter, the device, referred to as the "Rochester Cloak," uses inexpensive, everyday materials in its unique structure.

John Howell, a professor of physics at the University of Rochester, and graduate student Joseph Choi developed the device, which features four standard lenses that allows an object to appear invisible as the viewer moves several degrees away from the "optimal viewing position," Howell and Choi explain. Many scientists have approached the fundamental idea behind "cloaking," but instead use "high-tech or exotic materials," Howell says.

The "Rochester Cloak" is the first of its kind, Choi adds, as it's capable of "three-dimensional, continuously multidirectional cloaking." Howell told the Newscenter that he was inspired to make simple cloaking devices with common materials while working on a holiday project with his children.

How the "Rochester Cloak" works

In order to both cloak an object without disturbing the background, University of Rochester researchers determined the lens type, power needed and the precise distance between the lenses. In order to test their device, researchers placed the cloaked object in front of a grid background, the Newscenter explains.

Next, the scientists looked through the lenses, changing their point of view by moving from side to side. The grid would shift as expected, and as if the device wasn't even there.

How to make your own device

The scientists at University of Rochester provided steps on how to make your own cloaking device. Here's how to make your own "Rochester Cloak":

1. Purchase 2 sets of 2 lenses with different focal lengths f1 and f2 (4 lenses total, 2 with f1 focal length, and 2 with f2 focal length)
2. Separate the first 2 lenses by the sum of their focal lengths (So f1 lens is the first lens, f2 is the 2nd lens, and they are separated by t1= f1+ f2).
3. Do the same in Step 2 for the other two lenses.
4. Separate the two sets by t2=2 f2 (f1+ f2) / (f1-- f2) apart, so that the two f2 lenses are t2 apart.

Mashable notes efforts have been made for a real-life invisibility cloak over the last several years. However, none have quite been made available to muggles. Science will have to do, for now.