Scientists say they have slowed then stopped a squirt of light in what they describe as a key step towards the future of ultra-fast computing.

The technique, called 'trapped rainbow', would help optical data storage, with light replacing electrons to store information, according to their paper published today in the journal Nature.

Controlling light would also help engineers control major nodes where billions of optical data packets arrive at the same time.

By slowing some packets to let others through, rather like a traffic congestion scheme, the flow of data can be boosted.

The research, by Professor Ortwin Hess of the UK's University of Surrey and colleague Kosmas Tsakmakidis, is based on the so-called 'negative refractive index' of metamaterials.

Metamaterials are novel materials with metal components that are smaller than the wavelength of light, while the refractive index measures the slowing of light when it passes through an object.