The Internet is delivered to your home, place of work or favorite coffee shop by fiber-optic cables. Lying just underneath our feet, these cables carry data that travels as fast as the speed of light.

But those fiber-optic cables can be a bit of a nuisance for those who actually have to lay them, especially if you’re talking about doing so in remote places like deserts, or even outer space.

So, a team of researchers led by Howard Milchberg, professor of physics and electrical and computer engineering at the University of Maryland, is working on a plan to do away with those fiber-optic cables altogether, using just air to guide the light. That’s not an easy task, because the cables are needed for a very good reason – shoot a laser beam throught the air and it’ll spread apart and lose intensity the further it travels.

What fiber-optic cables do is create a kind of tunnel that allows the laser to travel to its destination without degrading in this fashion. It bounces along the cable without losing its intensity, which means data can travel across vast distances in milliseconds.

But Milchberg and his team have devised a way to make air mimic fiber-optic cables by creating a ‘wall’ of low-density air that’s surrounded by a core of much denser air. Called “air waveguides”, these invisible ‘tubes’ are created by firing short, powerful laser pulses through the air. As the laser beam passes, it heats the air, leaving behind a filament which is less refractive than the air which surrounds it.

These tubes can only sustain themselves for a few milliseconds, but that’s about a million times longer than the laser pulse itself. It’s therefore possible to send a second beam carrying data along the tube formed by the first laser. As Milchberg explains, “milliseconds is infinity” when you’re talking about lasers.

“It’s like you could just take a physical optical fiber and unreel it at the speed of light, put it next to this thing that you want to measure remotely, and then have the signal come all the way back to where you are,” said Milchberg in a release.

According to their tests, signals that passed through the ‘air cable’ were 1.5 times more powerful than those which were beamed through ‘normal’ air. The beams were transmitted a distance of three feet – the next step for the researchers will be to increase this range to 150 feet.

Illustration of an air waveguide. The filaments leave ‘holes’ in the air (red rods) that reflect light. Light (arrows) passing between these holes stays focused and intense.

Image credit: University of Maryland

As far as practical uses for this technology go, the team believes air cables could be used to facilitate communications in some of the world’s most remote locations, where it simply isn’t practical to go and start laying fiber-optics everywhere. They also believe air cables could be used to communicate with humans and machines in space. Furthermore, they say the technology could be used to probe the Earth and other planets to make topographic maps, or to examine chemicals in the atmosphere.

Main photo credit: TheAlieness GiselaGiardino²³ via photopin cc