Now You See It, Now You Don't: An Infrared Invisibility Cloak Made of Glass

From Tolkien's ring of power in The Lord of the Rings to Star Trek's Romulans, who could make their warships disappear from view, from Harry Potter's magical cloak to the garment that makes players vanish in the video game classic "Dungeons and Dragons", the power to turn someone or something invisible fascinates humankind. But who ever thought that a scientist at Michigan Technological University would be serious about building a working invisibility cloak?

That's exactly what Elena Semouchkina, an associate professor of electrical and computer engineering at Michigan Tech, is doing. She has found ways to use magnetic resonance to capture rays of visible light and route them around objects, rendering those objects invisible to the human eye.

They describe developing a nonmetallic cloak that uses identical glass resonators made of chalcogenide glass, a type of dielectric material (one that does not conduct electricity). In computer simulations, the cloak made objects hit by infrared waves -- approximately one micron or one-millionth of a meter long -- disappear from view. Earlier attempts by other researchers used metal rings and wires. "Ours is the first to do the cloaking of cylindrical objects with glass," Semouchkina said.

[atsimg]http://files.abovetopsecret.com/images/member/6401240e57f4.jpg[/atsimg]
Elena Semouchkina holds the ceramic resonators that enable her to make objects appear invisible in microwave frequencies.

Her invisibility cloak uses metamaterials, which are artificial materials having properties that do not exist in nature, made of tiny glass resonators arranged in a concentric pattern in the shape of a cylinder. The "spokes" of the concentric configuration produce the magnetic resonance required to bend light waves around an object, making it invisible.

Semouchkina and her team now are testing an invisibility cloak rescaled to work at mocrowave frequencies and made of ceramic resonators. They're using Michigan Tech's anechoic chamber, a cave-like compartment in an Electrical Energy Resources Center lab, lined with highly absorbent charcoal-gray foam cones.

There, antennas transmit and receive microwaves, which are much longer than infrared light, up to several centimeters long. They have cloaked metal cylinders two to three inches in diameter and three to four inches high.

"Starting from these experiments, we want to move to higher frequencies and smaller wavelengths," the researcher said. "The most exciting applications will be at the frequencies of visible light." So one day, could the police cloak a swat team or the Army, a tank? "It is possible in principle, but not at this time," Semouchkina said.

www.sciencedaily.com...

very cool, S+F from me,

in fact you get the very first S and F i have ever given since joining, so consider that a personal thanks for finding and posting the info.

This is the second time this year I've seen a story proclaiming an invisibility cloak to Infra Red light which isn't the same as invisible at all when they do it with visible light then OK that's cool.

Glass which doesn't let infra red light through has been commercially available for a long time and I think even normal glass does a pretty good job of blocking those frequency's. I don't see anything in the article that suggests anything but hiding an object from infra red light just to clarify.

I really don't get it. It's similar to me standing behind a wall then declaring the wall an invisibility cloak because the wall is blocking visible light. I don't doubt there is military potential in making objects invisible to thermal imaging but to call that an invisibility cloak is really exaggerating in my opinion.

As far as I'm concerned if I can see it with my eyes it isn't an invisibility cloak at best this might hide things from thermal cameras.

Originally posted by Teknikal
I really don't get it.

If you put an object behind the cloaked object, you'd see the object behind and not the cloaked object. The IR light flows around the cloak without disturbing it - much.

That's a bit different than standing behind a wall.

Yeah after I replied and thought about it a bit I figured out they were bending it round somehow instead of just blocking it which is cool and everything but I'll wait until it's done with visible light before being really impressed.

I'm sure this has some applications though but I can't help but picturing tanks or soldiers having to carry huge sheets of glass around and wondering if it does.

If they can ever achieve this with visible light they can call it an invisibility cloak and I'll be very impressed even if it's done with huge sheets of glass though, that would be pretty cool.