Researchers at Imperial College London say they’ve taken invisibility into the fourth dimension – time – by inventing a device that can hide whole events. It would give the impression of being a Star Trek transporter.
“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,” says Professor Martin McCall of the Department of Physics.
“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 team says the device would manipulate the propagation of light to create a ‘temporal void’, allowing undetectable moments of invisibility. The proof of concept design uses customised versions of optical fibres already used in telecommunications.
“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,” says McCall. “Light is then stitched back together seamlessly, so as to leave observers in ignorance.”
Unlike ordinary cloaking devices, 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,” says gaduate student Alberto Favaro.
The team is confident that the findings will trigger a race to create a practical spacetime cloak.