metamaterials, laser resin and invisibility cloaks

Metamaterials can bend light around objects to render them near-invisible, begins a recent report in New Scientist. But it is an imperfect, lossy process, meaning some light is absorbed on its way through the metamaterial, and therefore the object remains semi-visible.

Now a team of scientists at Purdue University in West Lafayette, Indiana have invented a light amplifying resin ‘sandwich filling’ which, when stimulated by a laser, creates gain in the electro-optical signal, restoring the ‘lost’ light. The “negative-index metamaterial” means that an object can now conceivably be made  invisible to specific wavelengths of light.

Previous metamaterials, utilising nanoholes in a carbon matrix, IIRC, were able to mask objects in the microwave end of  the electromagnetic spectrum, but visible light has until now been elusive.

A wearable device is still light years away (pardon the pun!), but military installations, ships and even armoured vehicles are most definitely foreseeable near-term applications for the invisibility treatment.

Watch this space. Not that you’ll see anything

coast clear for invisibility cloak?

For now, the invisibility cloak remains a thing of science fiction

From BBC News, Thursday 20th August 2009

A physicist has said he hopes to make major advances in the field of invisibility in the next two years.

Professor Ulf Leonhardt at St Andrews University is working on a blueprint for a cloaking device that could also be used to shield coast lines.

The researcher, who cites the Invisible Woman and Harry Potter as inspiration, has been working on the concept of invisibility since 2006.

The project will focus on a connection between light and curved space.

Prof Leonhardt, who describes his invisibility work as “geometry, light and a wee bit of magic”, hopes to manipulate modern metamaterials – or “designer atoms” to create an invisibility device using the laws of refraction.

He believes that in bending light, transparent materials like glass or water appear to distort the geometry of space, which is the cause of many optical illusions, including invisibility.

‘Extreme ideas’

Prof Leonhardt said: “The idea of invisibility has fascinated people for millennia, inspiring many myths, novels and films.

“In 2006, I began my involvement in turning invisibility from fiction into science, and, over the next two years, I plan to develop ideas that may turn invisibility from frontier science into applicable technology.”

Although the professor admitted it was difficult to predict possible applications, he suggested invisibility research could be used to improve visibility, leading to the development of the perfect retroreflectors (cats eyes), better microscopes and improved lenses.

He added: “I will most certainly find easier ways of cloaking, but it remains to be seen how practical they are.

“The important thing is to understand the foundations and come up with something new or take an existing idea to extremes; using technology and ideas to make things happen – technology we cannot imagine would ever exist.”

The project is being funded by the Royal Society’s Theo Murphy Blue Skies Award.

scientists claim closer to success with invisibility shield

Looks like a great story, doesn`t it? From scence fiction to science fact. But the full scoop from Defence Tech is another example of “nothing to see here, move along please”.

There is a pie in the sky - can you see it?

The article states that

according to Dr. Richard Hammond, a theoretical physicist with the Optical Physics and Imaging Science department of the Army Research Office, engineers are closer than they’ve ever been to developing a material that can bend light around an object rendering it invisible to certain wavelengths — light being one of them.

It claims

there are some significant obstacles to making a usable “invisibility cloak,” however.

But get this:

“in early applications we could shield an object from radar,” Hammond added.

So apparently some boffins have reinvented RAM (radar absorbent material) as used on stealth planes and ships. Whoopee-frickin`-doo!

Hey, you know what? I`ve come up with this great concept: It`s basically a disc with a hole in the middle. I think if you put some sort of rod through the hole you could rotate the disc around it, and if you had a disc on the other end, you would be able to hold the rod off the ground with them. I call it a centrally rotating axial perambulation device. I`m sure there must be thousands of practical applications for it. Perhaps the guys at the Army Research Office could find a use for it. If they haven`t already invented it, that is.