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Researchers developing cloaking device that can ‘stop’ time

- The Washington Times - Wednesday, August 14, 2013

Imagine a thief who could cover an item on a shelf with a cloaking device, steal the item, and for all intents and purposes cause the missing item to appear untouched to the human eye. Researchers at Northwestern University are close to making such technology a reality.

Extreme Tech reports that the researchers have designed such a device, using mirrors to block the visible spectrum from the human eye:

The temporal cloak, designed by mathematician Miguel Lerma, uses four normal mirrors (B, C, F, G) and four electrically switchable mirrors (A, D, E, H) that can be switched between fully reflective, fully transparent, or anywhere in between. Basically, for us to perceive an event — such as a clock hand moving — light has to bounce off the clock and strike the back of our eye. This happens at the speed of light, which over a short distance is essentially instantaneous. If you slow down the light before it reaches the object, however, it creates a period where the object isn't illuminated — and therefore you cannot see the event. …

The process is somewhat complex, but by changing the reflectivity of the four electrically switched mirrors, events that occur at the object (O) can be hidden from the observer.

While the device has not yet been created, Extreme Tech notes that because the science is sound, there is no reason why it couldn't be "implemented today, using existing and readily available materials."

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