Pulses of light are the absolute fastest way to transfer data (because nothing's faster than light), but old school fiber optic cables can only go so many places. Scientists have a new idea: use high-powered lasers to make a column of low-density air that can carry a light signal just as well as a normal cable. Yes, fiber optics made of thin air.
Get ready to dust off your freshman physics knowledge. Dr. Howard Milchberg and his team at the University of Maryland found that very powerful laser blasts collapse the air around them into a narrow beam called a filament. These filaments of hot air then expand, opening up a tube of low density air. This hole has a lower refractive index than undisturbed air-in other words, it's like a mirrored tube.
In a paper published today, Dr. Milchberg and team showed that four such lasers fired in a square arrangement create a cage of low-density air columns. A fifth laser beam shot down the middle will stay trapped between these four columns (show in red above), since the low density air reflects light. In other words, the four mirrored tubes trap the laser beam in the center, focusing it on its target instead of allowing it to scatter in the air, as diagrammed with black arrows in the above illustration.
All of this happens astonishingly quickly. The filaments themselves disappear after just one-trillionth of a second, but the low-density holes, the reflective tubes that form the boundary of this air-cable, takes a billion times longer to appear. All told, the "air cable" created by the laser pulses survives for a few milliseconds-plenty of time to blast a data beam through. As Dr. Milchberg said in the announcement of the findings, "milliseconds is infinity" when it comes to laser transmission.
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