A time cloak has been created which tears a hole in time itself, allowing data to be hidden and transmitted over fiber optic cables without ever showing it was there.
Using phase modulators, a common piece of optical equipment, to bend light, the device hides data in time itself. Based on a principle known as the Talbot effect, which creates repeated self-images of a grating when light passes through it from diferent directions, this device creates a laser pulse packed with data, then closes it back up again.
Two phase modulators at each end of the communications stream speed up the front end of waves and slow down their trailing edges. When the crest from one wave packet aligns with the trough of another wave, it makes it look like no signal was ever sent. The researchers, led by Andrew Weiner of Purdue University, discovered that this effect could cloak transmitted data at 12.7 gigabits per second - fast enough for fiber optic communications.
The major challenge with such as system is that not only can the signal not be seen by someone attempting to spy on the signal, it can't be seen by the person to whom you intend to send the signal, either.
"We erased the data-adding event entirely from history. There's no way that data could be sent as a useful message to anyone, even a genuine recipient," Joseph Lukens, lead author of the study, said.
Theoretically, the new device could be used by a theif to go into a bank, and have the cameras not record his image until after he was gone.
A similar device was demonstrated in January 2012, but that mechanism could only hide about 1/10,000 of the data sent through it - not nearly powerful enough for data transmission. The new device can cloak 46 percent of the data, enough to encode current data. While the older device used a pricey femtosecond laser, the laser used to create the pulses in the new device is common equipment.
"This potential to cloak real-world messages introduces temporal cloaking into the sphere of practical application with immediate ramifications in secure communications," Weiner said.
Announcement of the device was announced in an advance online copy of the journal Nature on June 5.
