The potential for light waves to carry terabits of data every second through free space is reported in Nature Photonics this week. This work could aid the development of high-efficiency, high-bandwidth satellite communication links.

The technique involves carrying data on a ‘twisted’ light beam, whose ‘front’ is helical in shape. Jian Wang, Alan Willner, and colleagues show that combining beams with differing amounts of twist - formally known as orbital angular momentum - allows up to 2.56 terabits of data to be transmitted over free space every second. They also demonstrate that it is possible to separate and swap data between the twisted beams.

Researchers in optical communications often boost data transfer speeds by combining light beams of different colours or polarizations. This new technique demonstrates that orbital angular momentum can also be used in this fashion, thus providing optical scientists with a new tool for further improving the speed and functionality of their systems.