New 'Time Cloak' Hides Optical Communications from Secret Eavesdroppers

Before you think that "time cloaks," or temporal cloaks, have anything to do with the Doctor, think again. They don't allow users to travel through time like a certain blue box, but they do have a myriad of practical applications. Researchers have recently developed a method for temporal cloaking that could essential hide optical communications and prevent secret eavesdroppers from listening in to telecommunications.

Temporal cloaking is nothing new. In 2012, researchers invented the method, though it only cloaked a tiny fraction of the time available for sending data in optical communications--only about a 10,000^th of a percent overall. Needless to say, the method was good in theory, but not in practice. Yet now, researchers have upped that number to 46 percent, which could actually make the concept practical for commercial applications.

So what exactly does this technique do, anyway? Essentially, temporal cloaking manipulates the phase, or timing, of light pulses. The creation of light can be likened to waves in the ocean. If one wave is going up and interacts with another wave that's going down, they cancel each other out and the light has zero intensity. The phase determines the level of interference between these two waves. In fact, any data in regions where the signal is zero would be cloaked.

It doesn't just cloak the signal, though. The technology is also sneaky about doing so. In temporal cloaking, two phase modulators, an essential piece of equipment that's often found in optical communications to modify signals, are used to first create the holes and two more to cover them up. This makes it look as though nothing was done to the signal at all.

"It's a potentially higher level of security because it doesn't even look like you are communicating," said Joseph Lukens, one of the researchers, in a news release. "Eavesdroppers won't realize the signal is cloaked because it looks like no signal is being sent."

In fact, the technique could be used in the military, homeland security or law enforcement in order to make communications safer. But it doesn't just make communications safer; it could also disrupt communications between others.

"It might be used to prevent communication between people, to corrupt their communication links without them knowing," said Lukens in a news release. "And you can turn it on and off, so if they suspected something strange was going on you could return it to normal communication."

Currently, the researchers are looking to improve the operational bandwidth of the percentage of cloaking beyond 46 percent. While the tool is already useful, increasing the amount it covers could make it even more valuable. While the method may have nothing to do with the Doctor, it's still pretty cool--like Stetson hats and bow ties.

The findings are published in the journal Nature.