Twisted Light Transmission

November 19th, 2014 by

Researchers from the University of Vienna and the Institute for Quantum Optics and Quantum Information in Vienna have transmitted twisted light beans over a large outdoor distance. Twisted light allows for transmitting a huge amount of data by twisting the light into a corkscrew shape, so that the rotation allows for encoding data on additional channels, for both classical and quantum communications. The light can be theoretically twisted with an infinite number of turns with each configuration acting as a single communication channel. Previous experiments using twisted light over fiber-optic links show that twisted-light can be used to transmit 2.5 terabits of data per second, but these were always using optical fibers. Sending twisted light over free space while avoiding disturbances from air turbulence has thus far only been achieved over small distances in a lab environment. The researchers used a green laser beam to send twisted light through a lens on top of a radar tower. They sent 16 different twisted configurations of a specific wavelength of light to a receiver 3 km away. A camera was used to capture the beams of light and an artificial neural network was deployed to reveal the pattern and remove any possible disturbances that may have been caused by air turbulence. The researchers encoded the light with real information. The orbital angular momentum of light is theoretically unbounded, meaning that one has an unlimited amount of different distinguishable states in which light can be encoded. It is envisaged that this additional degree of freedom could significantly increase data-rates in classical communication.

Source: IOP

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