Boffins promise see-through walls

Scientists from Imperial College London and the University of Neuchâtel in Switzerland have developed a substance that could be used to build see-through walls.

The material which can be made transparent under the right conditions, has potential uses in buildings to allow contractors to check cabling without burrowing into wall space, or to help rescuers searching through rubble for survivors after an earthquake.

"This real life 'x-ray specs' effect relies on a property of matter that is usually ignored: that the electrons it contains move in a wave-like way," explained Professor Chris Phillips of Imperial College.

"What we have learnt is how to control these waves directly. The results can be pretty weird at times, but it's very exciting and so fundamental."

The substance, which has been created only in laboratory conditions, is based on a breakthrough which contradicts one of Einstein's theories.

Einstein calculated that the atoms within materials must be excited with energy to make them emit rather than absorb light.

But quantum physicists have created specially patterned crystals only a few billionths of a metre in length that behave like 'artificial atoms'.

When light shines into the crystals, it becomes entangled with them at a molecular level rather than being absorbed, causing the material to become transparent.

The team also discovered that light passing through this new material slows down and could be completely stopped and stored. Professor Phillips believes this has important implications for secure information networks.

"When we send information, for example by sending light pulses down optical fibres, it can only be accessed by making a form of measurement, and these measurements always disturb the information," he said.

"This technology offers us a means of sending light signals through a network without having to disturb them ourselves. Now, if confidential information is being spied on, the disturbance shows up straightaway and we can nab the eavesdropper with 100 per cent certainty."