A 'perfect' cloak of invisibility has been demonstrated for the first time.

(But no, it's not quite Predator-style stuff yet.)

Researchers have been able to render a centimetre 7.5 cm in diameter and 1cm tall invisible to microwaves.

The trick was made possible by creating a diamond-shaped region in which light was perfectly diverted around the object.

The illusion only works from one direction, however - and the team behind the Nature Materials study say it would be very difficult to reproduce with visible light.

Still, it represents the first time that the theory of "transformation optics" developed by John Pendry of Imperial College London and David Schurig and David Smith of Duke University in 2006 has been shown to work without approximations.

Usually, attempts to show this effect in action result in imperfections around the edges which show up the object being made invisible.

But in this experiment, there were no reflections.

Professor Smith of Duke, who was also involved in the new experiment with colleague Nathan Landy, said it was the first cloak to achieve "perfect" invisibility.

The breakthrough could have implications for telecommunications and radar, where transmission of microwaves and other wavelengths of light without distortion can be crucial.

nathan landry