November 1, 2017
The University of Glasgow says scientists have taken an important step towards using ‘twisted’ light as a form of wireless, high-capacity data transmission which could make fiber-optics obsolete.
In a new report published recently in the journal Science Advances, a team of physicists based in Canada, the U.K., Germany and New Zealand describe how new research into ‘optical angular momentum’ (OAM) could overcome current difficulties with using twisted light across open spaces.
According to a release issued by the university, “scientists can ‘twist’ photons — individual particles of light — by passing them through a special type of hologram, similar to that on a credit card, giving the photons a twist known as optical angular momentum.
“While conventional digital communications use photons as ones and zeroes to carry information, the number of intertwined twists in the photons allows them to carry additional data – something akin to adding letters alongside the ones and zeroes. The ability of twisted photons to carry additional information means that optical angular momentum has the potential to create much higher-bandwidth communications technology.”
The researchers, meanwhile, added that while “optical angular momentum techniques have already been used to transmit data across cables, transmitting twisted light across open spaces has been significantly more challenging for scientists to date. Even simple changes in atmospheric pressures across open spaces can scatter light beams and cause the spin information to be lost.
They examined the effects on both the phase and intensity of OAM carrying light over a real link in an urban environment to assess the viability of these modes of quantum information transfer.
Dr. Martin Lavery, head of the Structured Photonics Research Group at University of Glasgow, and lead author on the team’s research paper, said that “in an age where our global data consumption is growing at an exponential rate, there is mounting pressure to discover new methods of information carrying that can keep up with the huge uptake in data across the world.
“A complete, working optical angular momentum communications system capable of transmitting data wirelessly across free space has the potential to transform online access for developing countries, defence systems and cities around the world.
“Free space optics is a solution that can potentially give us the bandwidth of fibre, but without the requirement for physical cabling. This study takes vital steps forward in the journey towards high dimensional free space optics that can be a cheaper, more accessible alternative to buried fiber optics connections.”
Dr Lavery undertook the work in partnership with researchers from the Max Planck Institute for the Science of Light and Institute of Optics, and the Universities of Ottawa, Otago and Rochester.
The paper, entitled ‘Free-space propagation of high dimensional structured optical fields in an urban environment,’ is published in Science Advances. The work was funded by Royal Academy of Engineering, EPSRC and supported by the International Max Planck Partnership.