The rainbow test was a step towards better
control of light for computing, showing that
dynamic localization of electrons works as
predicted.
Image: iStockphoto

A new approach to trapping rainbows could lead to a form of computing that uses many different colours of light at once to convey information, according to an international research team.

The control and manipulation of multi-coloured light is expected to have applications in optical data processing and storage, photonic devices that can be used in optical communication networks, and integrated photonic signal processors.

Mr Ivan Garanovich, Dr Andrey Sukhorukov, and Professor Yuri Kivshar from The Australian National University and their colleagues from the University of Jena in Germany have developed an innovative approach for controlling coloured. Their results are published in the latest edition of Nature Physics.

“The speed of light sets the maximum possible limit for the speed at which information can be transmitted,” explained Professor Yuri Kivshar from the Nonlinear Physics Centre in the ANU College of Physical Sciences. “Nowadays, real-time global communications and ultra-fast supercomputers rely on laser pulses to carry bits of data. Physicists invented the so-called white-light laser, which emits all colours in the spectrum at once. This is useful as different colours of light can be used to transmit many data streams at the same time.

“Whereas data processing is currently performed in electronic devices, faster speeds may be achieved by manipulating optical streams directly, the goal actively pursued at research centres worldwide. This requires the development of means to manipulate light in a similar way to how we can influence electrons.

“Electrons are tiny charged particles, and their motion can be controlled through an applied electric field. However photons, the particles of light, have no charge. So we needed to develop another method to manipulate light. We devised a set of tiny channels in glass, and observed the fundamentally important effect of dynamic localization, which was originally predicted for electrons. For light, this is visible as the appearance of tiny rainbows followed by their recombination back into white light, and this was directly observed in experiments by our collaborators at the University of Jena.”

Professor Kivshar said the result is exciting because it is the essential step towards using light as a more comprehensive medium for information, which could ultimately lead to the development of computers and forms of communication many times more powerful than those currently in existence.