Research from Imperial College London is now taking cloaking invisibility using metamaterials into the fourth dimension — time — creating the potential to hide whole events, so an object could move from one region of space to another, completely unseen by anyone watching.

Research published today (November 16, 2010) in IOP Publishing’s Journal of Optics explains how the propagation of light can be manipulated to create a “temporal void,” allowing undetectable moments of invisibility.

As lead author, Professor Martin McCall from the Department of Physics at Imperial College London, explains, “Our spacetime ‘event’ cloak works by dividing illuminating light into a leading part, which is sped up and passes before an event, and a trailing part, which is slowed down and passes after. Light is then stitched back together seamlessly, so as to leave observers in ignorance.”

Graduate student Alberto Favaro explains further, “It is unlike ordinary cloaking devices because it does not attempt to divert light around an object. Instead it pulls apart the light rays in time, as if opening a theatre curtain, creating a temporary corridor through which energy, information, and matter can be manipulated or transported undetected.”

Their proof of concept design uses customised versions of optical fibers used in telecommunications to achieve the feat.

The team is confident that their findings will initiate a race to create a practical spacetime cloak.

“We have shown that by manipulating the way the light illuminating an event reaches the viewer, it is possible to hide the passage of time,” said McCall. “Not only can specific events be obscured, but it is possible for me to be watching you and for you to suddenly disappear and reappear in a different location.”

The optical breakthrough also promises advances in signal-processing applications and quantum computing, which depends on the manipulation of light for the safe transmission of data.

Reference (available free): A Spacetime Cloak, or a History Editor

Adapted from materials provided by the Institute of Physics

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