Light unbound: Data limits could vanish with new optical antennas

[Jim__]

From phys.org:

Researchers at the University of California, Berkeley, have found a new way to harness properties of light waves that can radically increase the amount of data they carry. They demonstrated the emission of discrete twisting laser beams from antennas made up of concentric rings roughly equal to the diameter of a human hair, small enough to be placed on computer chips. Credit: Boubacar Kanté

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The new work, reported in a paper published Thursday, Feb. 25, in the journal Nature Physics, throws wide open the amount of information that can be multiplexed, or simultaneously transmitted, by a coherent light source. A common example of multiplexing is the transmission of multiple telephone calls over a single wire, but there had been fundamental limits to the number of coherent twisted lightwaves that could be directly multiplexed.

"It's the first time that lasers producing twisted light have been directly multiplexed," said study principal investigator Boubacar Kanté, the Chenming Hu Associate Professor at UC Berkeley's Department of Electrical Engineering and Computer Sciences. "We've been experiencing an explosion of data in our world, and the communication channels we have now will soon be insufficient for what we need. The technology we are reporting overcomes current data capacity limits through a characteristic of light called the orbital angular momentum. It is a game-changer with applications in biological imaging, quantum cryptography, high-capacity communications and sensors."

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But beyond frequency and polarization is orbital angular momentum, or OAM, a property of light that has garnered attention from scientists because it offers exponentially greater capacity for data transmission. One way to think about OAM is to compare it to the vortex of a tornado.

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