Physicists have sent a beam of twisted light 3km through the air above Vienna, the first time that information has been transmitted outdoors using the “twist” of a visible light beam.
This twisting property could allow very fast communication because light with different amounts of twist, encoding separate channels of information, could be sent simultaneously.
Reported in the New Journal of Physics, the technique was tested by sending black-and-white portraits of three famous Austrians: physicists Ludwig Boltzmann and Erwin Schroedinger, and composer Wolfgang Amadeus Mozart.
Above the rooftops of Mozart’s own city, his portrait was broken down into pixels and travelled through the night inside a green laser beam.
