Though it may have seemed like science fiction a short time ago, the idea of an invisibility cloak is now very much a possibility.
Scientists in the United States and England have created a cloaking instrument that makes an object invisible if viewed with microwaves, according to a study recently published in the academic journal Science.
David Schurig and David R. Smith of Duke University in North Carolina and John Pendry of Imperial College in London, England, laid out a theory in May that such an achievement would be possible, according to the article.
The device does not make an object hidden from visible light, but it redirects microwaves around the object to the other side to make the appearance that the particles passed by the device virtually unobstructed.
“It’s the notion of making light waves flow around objects rather than bounce off them,” said Jeffrey Cina, a University physical chemistry professor who also works in the Oregon Center for Optics. “It’s sort of like water flowing around a post in a pier.”
The Duke team of scientists produced the device in October, just five months after the initial prediction.
“It’s sort of a demonstration of principle, something that had been known to be a theoretical possibility,” Cina said.
Cina said he was impressed with how quickly the cloaking device was developed after the idea was presented.
Hailin Wang, a University physics professor also in the Oregon Center for Optics, said the University does not do any work with microwaves as the team from Duke University did for its research.
The cloak does have its limitations, as it is the first of its kind.
“In the optical visual field it’s not invisible,” Wang said. “That’s probably still far away.”
Still, the scientists involved say it is a significant achievement that could lead to later developments, according to the Science article.
Cina said these additional scientific advances that could come from the cloaking device could be more practical down the line. He also said it potentially could provide a way to avoid damage from overexposure to optical waves.
University Physics assistant professor Jens Noeckel said the technology might be applied to avoiding radar more immediately, though such applications are still far off.
The device is a simple circular structure made of “metamaterials,” which are a series of fiberglass rings with smaller rods and rings that microwaves pass through. The cloak only works for microwaves with a wavelength of 3.5 centimeters, according to the article.
“It sounds like the next challenge is to broaden the range of frequencies,” Cina said.
Noeckel said expanding the theoretical possibilities of the technologies to more practical applications with visible light may be more difficult than advertised. He said microwaves are much larger in size than visible light waves, and the metamaterials for this particular device have been specifically manufactured for only one wavelength of microwaves.
“If you want to make this stuff work with optical light, you have to make the metamaterials much smaller,” Noeckel said. He said the theories are there, but applying them is a greater task.
“The idea is really quite simple, but the challenge is really the material aspect of it – trying to make the light move and bend in just the right way,” Noeckel said.
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