Original URL: http://www.theregister.co.uk/2010/07/22/invisible_greenhouse/

Boffins develop greenhouse invisible to night-vision goggles

'Glass cloak' would show up on thermal imagers, though

By Lewis Page

Posted in Science, 22nd July 2010 15:17 GMT

Boffins in the States say they have designed a "glass cloak" which renders objects within it invisible in the infrared spectrum.

Prof Elena Semouchkina and her colleagues developed the "cloak", which reportedly bends micron wavelengths around its interior. Micron-length waves are in the near infrared, the part of the electromagnetic spectrum used by ordinary night-vision goggles.

Previous invisibility cloak research has tended to focus on metallic "metamaterials", but Semouchkina and her colleagues' design calls for magnetic resonator metamaterial made of chalcogenide dielectric glass.

Regular metallic "cloaks", according to heavyweight invisibility prof Sir John Pendry, are not - or rather, will not be when visible-light versions are developed - actually flexible cloaks. Rather, they would be hefty rigid structures or cladding, more like a shed than any type of garment.

It appears that Semouchkina's chalcogenide glass is pretty rigid, too, so in fact here we're talking more about an invisible greenhouse or glass house than a cloak.

The invisible glass dwelling - doubtless featuring a glass ceiling of the type known to impede upwardly-mobile lady biz execs - would of course be perfectly perceptible to the naked eye. However it would be an ideal hiding place for people needing to elude enemies wearing regular near-infrared night-vision goggles, whether passive or active.

Sadly more up-to-date opponents using thermal imagers working in longer infrared wavelengths could detect it without too much difficulty: though one should note that human body heat can't normally penetrate glass, so the thermal-imager user would need to distinguish the invisible greenhouse by differentiating it from its background.

For now, though, the disappearing glass abode doesn't exist in the real world. Semouchkina and her colleagues verified the theory of in vitro vanishment in silico - that is, they ran some computer simulations rather than actually building their machine.

Their paper, An infrared invisibility cloak composed of glass, can be read here (abstract free, payment/subscription required for the full article). ®