Pioneering research by an international team of scientists, including from the University of Exeter, has developed techniques that will allow the first memory chip that can capture light. The key breakthrough will allow large quantities of data to be stored directly on an integrated optical chip, rather than being processed and stored electronically, as happens today.

Light is ideally suited to ultra-fast high-bandwidth data transfer, and optical communications form an indispensable part of the IT world of today and tomorrow. However, a stumbling block so far has been the storage of large quantities of data directly on integrated chips in the optical domain.

While optical fibre cables - and with them, data transfer by means of light - have long since become part of our everyday life, data on a computer are still processed and stored electronically.

The team of scientists from Germany and England have made a key breakthrough by capturing light on an integrated chip, so developing the first permanent, all-optical on-chip memory.

The research is published in leading scientific journal, Nature Photonics.

Professor David Wright, from the University of Exeter's Engineering department said: "With our prototype we have, for the first time, a nanoscale integrated optical memory that could open up the route towards ultra-fast data processing and storage. Our technology might also eventually be used to reproduce in computers the neural-type processing that is carried out by the human brain."

Professor Wolfram Pernice, from the Institute of Physics at Munster University and who led the work said: "The all-optical memory devices we have developed provide opportunities that go far beyond any of the approaches to optical data processing available today."

"Optical bits can be written in our system at frequencies of up to a gigahertz or more," adds Professor Harish Bhaskaran from Oxford University in England, one of the lead co-authors, "and our approach can define a new speed limit for future processors, by delivering extremely fast on-chip optical data storage" In addition, he says, "the written state is preserved when the power is removed, unlike most current on-chip memories".

The scientists from Oxford, Exeter, Karlsruhe and Munster used so-called phase change materials at heart of their all-optical memory. The distinguishing feature of these materials is that they radically change their optical properties depending their phase state, i.e. depending on the arrangement of the atoms in the material. This changeability - between crystalline (regular) and amorphous (irregular) states - allowed the team to store many bits in a single integrated nanoscale optical phase-change cell.