Vortices could boost light’s information capacity

Ars Technica : Orbital angular momentum is one of the quantum properties of photons and has a theoretically infinite number of possible values. This makes it a subject of interest for researchers trying to increase the amount of data a single photon can represent. A team led by Xinlun Cai of the University of Bristol in the UK may have taken the first real steps toward that goal. The researchers shined IR laser light through ring-shaped silicon chambers scored with grooves, which diffracted the light, causing helical interference patterns. The patterns were dependent on the photons’ original polarization and the diameter and grooving of the ring chambers. The team also created additional patterns by combining light that passed through different rings. Data transfer is only one possible use for orbital angular momentum manipulation, but researchers must overcome the loss of pattern coherence due to interactions with molecules in air or fiber-optic cables before it is useful in quantum devices.