Scientists have come a step closer to super-fast optical computing thanks to European research into the mysterious properties of "fast and slow" light.

A recent European Science Foundation (ESF) workshop focused on this phenomenon, which arises from the dispersion of electromagnetic waves when they interact with, and travel through, a physical medium such as a crystal.

This can have the effect of slowing down the light pulses, or on occasions appearing to cause local acceleration.

These speed variations have the potential for purely optical devices using just electromagnetic radiation, rather than electrical signals, to store and process information.

The ESF project achieved its objectives of reviewing current research in the field, highlighting possible applications and gathering a dispersed European community of scientists, according to the workshop's convenor Marco Santagiustina.

"There were two remarkable highlights: slow and fast light research has immense potential in applications like microwave and millimetre wave photonics, " he said.

"Secondly, such applications can be targeted by making progress in a selected set of technologies."

Santagiustina explained that purely optical devices are still some way off. But in the more immediate future, the project hopes to use these properties to enhance existing hybrid communication systems combining electronic and photonic devices.

Another more immediate application is likely to come from the ability to process ultra wide band microwave signals for radio communications in mobile telephony and wireless Lans.

"Fast and slow light can be harnessed to transmit radio frequencies directly over fibre, making it easier, cheaper and more efficient to connect base stations or wireless access points," said Santagiustina.

"Radio over fibre is an existing application field destined to grow in the near future, and will represent a significant step forward for photonic/electronic convergence.

"The time-delay/phase-shift provided by slow and fast light devices can yield unprecedented functions."