Original URL: http://www.theregister.co.uk/2013/06/11/invisibility_cloak_using_natural_light/

Boffins hide cute kitty behind invisibility shield

No polarisation or microwaves needed, yet the cat and fish disappear

By Richard Chirgwin

Posted in Science, 11th June 2013 06:06 GMT

Vid It's not going to actually fool everyone, but a China-Singapore partnership has demonstrated an “invisibility cloak” that works with natural light.

While still pretty crude, the demonstration beats prior work in one key characteristic: it doesn't need polarised light (or microwaves) as previous cloaking demonstrations have done.

The researchers took work by John Pendry (Wikipedia entry here), but because they were working with natural light, they realised that it's not necessary to preserve the phase of the light they're bending.

That's because unlike demonstrations using polarised light or microwaves, natural light is chaotic, and human eyes aren't phase sensitive.

“This allows the cloak design to be made in large scale using commonly available materials and we successfully report cloaking living creatures, a cat and a fish, in front of human eyes,” they write in their paper at Arxiv (PDF).

“By abandoning the phase preservation requirement it is possible to create invisibility cloaking for natural light in multiple observation angles”, they say.

Because it uses rigid glass, the invisibility cloak is of only limited use: it can't “wrap” its subject, and only works when the subject moves behind the glass – but it works, they say, “where only a certain number of detectors or observers are involved”.

First, play spot the goldfish …

Watch Video

...and now, the cat.

Watch Video

The work was conducted by scientists from China's Zhejiang University, Nanyang Technological University in Singapore, with support from the University of Southampton and Boston's Marvell Technology Group, and was led by Baile Zhang from Nanyang. ®