Invisibility Cloak for Time Itself
While a range of ingenious man-made materials bring us ever closer to realizing the possibility of cloaking objects from visible light, research from Imperial College London is now taking invisibility into the fourth dimension — time — creating the groundbreaking potential to hide whole events.
The laws of physics might make the creation of a transporter which can dematerialize objects and then rematerialize them elsewhere a little beyond us, but it is now being suggested that an object could move from one region of space to another, completely unseen by anyone watching. Research published 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, Martin McCall from the Department of Physics at Imperial College London, explains, “Our space-time ‘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.”
Courtesy of Imperial College London
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.”
Researcher Paul Kinsler is enthusiastic about their proof of concept design which uses customized versions of optical fibers already used in telecommunications to achieve the feat. The team is confident that their findings will initiate a race to create a practical space-time cloak. Martin McCall continues, “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.”
As well as making a safe-cracking thief’s dreams come true, the optical breakthrough promises exciting advances in quantum computing, which depends on the manipulation of light for the safe transmission of vast amounts of data. Besides the science-fiction capabilities of the event cloak, signal-processing applications will play a key role in driving research forward on this topic.