Cloaking device pulls apart light rays in time

According to research published in IOP Publishing's Journal of Optics, the propagation of light can be manipulated to create a 'temporary void' allowing undetectable moments of invisibility. Lead author, Prof Martin McCall from the Department of Physics at Imperial College London, explained: "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 noted: "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." Researcher Dr Paul Kinsler is enthusiastic about their proof of concept design which uses customised versions of optical fibres already used in telecommunications to achieve the feat. The team hopes that their findings will initiate a race to create a practical spacetime cloak. Professor Martin McCall added, "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. 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 promises advances in quantum computing, which depends on the manipulation of light for the safe transmission of vast amounts of data. Signal processing applications will play a key role in driving research forward on this topic.