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Lasers Make a Fiber Optic Cable Out of Thin Air

Just like a fiber optic cable, without the physical cable

smithsonian.com

Electronic signals sent through the air spread out as they travel, growing weaker the farther they get from their source. Think of radio waves emanating from a tower, and the fading signal when you drive too far. This is true for your cell phone as much as it is for a highly-tuned laser.

Cables, in contrast, keep an electronic signal confined and focused. They're what let high speed internet communications crisscross the planet in the blink of an eye. But cable communication needs physical cables, and cables are expensive.

In a new study, physicists at the University of Maryland have come up with a solution that is the best of both worlds: they've coaxed thin air into acting like a fiber optic cable, a trick of physics that could allow for long-distance communication without all the cords.

As light moves down a fiber optic cable it bounces side-to-side within the glass or plastic tube, keeping it confined. The scientists figured out a way to coax air to change such that light passes through it in much the same way, says New Scientist.

The team shone four lasers in a square arrangement, heating air molecules and creating a low-density ring around a denser core of air. Light bounces around the dense core just like in a fibre.

Using this technique, the researchers could make the careful arrangement of air last long enough to send a signal, explains a statement from the University of Maryland:

Importantly, the “pipe” produced by the filaments lasted for a few milliseconds, a million times longer than the laser pulse itself.  For many laser applications, Milchberg says, “milliseconds is infinity.”

So far, the team have manage to make an air-fiber a few feet long. But if the technology can be scaled up, the possibilities are endless. According to Howard Milchberg, the lead scientist on the team, it would be like having "an optical fiber cable that you can reel out at the speed of light."

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About Shannon Palus

Shannon Palus is a science writer, and a researcher for Popular Science. Her work has appeared in Discover, Slate, Ars Technica, and elsewhere. She is based in Philadelphia.

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