Pretty interesting stuff, if true:
-> THEORETICAL BLUEPRINT FOR INVISIBILITY CLOAK REPORTED
->
-> Note to editors: David R. Smith can be reached at drsmith@ee.duke.edu or
-> (919) 660-8258; David Schurig can be reached at david.schurig@duke.edu
-> or (919) 660-8259. More information about metamaterials is available at
-> http://www.ee.duke.edu/~drsmith.
->
-> DURHAM, N.C. – Using a new design theory, researchers at Duke
-> University’s Pratt School of Engineering and Imperial College London
-> have developed the blueprint for an invisibility cloak. Once devised,
-> the cloak could have numerous uses, from defense applications to
-> wireless communications, the researchers said.
->
-> Such a cloak could hide any object so well that observers would be
-> totally unaware of its presence, according to the researchers. In
-> principle, their invisibility cloak could be realized with exotic
-> artificial composite materials called “metamaterials,” they said.
->
-> “The cloak would act like you’ve opened up a hole in space,” said David
-> R. Smith, Augustine Scholar and professor of electrical and computer
-> engineering at Duke’s Pratt School. “All light or other electromagnetic
-> waves are swept around the area, guided by the metamaterial to emerge on
-> the other side as if they had passed through an empty volume of space.”
->
-> Electromagnetic waves would flow around an object hidden inside the
-> metamaterial cloak just as water in a river flows virtually undisturbed
-> around a smooth rock, Smith said.
->
-> The research team, which also includes David Schurig of Duke’s Pratt
-> School and John Pendry of Imperial College London, reported its findings
-> on May 25, 2006, in Science Express, the online advance publication of
-> the journal Science.
->
-> The work was supported by the Defense Advanced Research Projects Agency.
->
-> First demonstrated by Smith and his colleagues in 2000, metamaterials
-> can be made to interact with light or other electromagnetic waves in
-> very precise ways. Although the theoretical cloak now reported has yet
-> to be created, the Duke researchers are on their way to producing
-> metamaterials with suitable properties, Smith said.
->
-> "There are several possible goals one may have for cloaking an object,”
-> said Schurig, a research associate in electrical and computer
-> engineering. “One goal would be to conceal an object from discovery by
-> agents using probing or environmental radiation.”
->
-> “Another would be to allow electromagnetic fields to essentially pass
-> through a potentially obstructing object,” he said. “For example, you
-> may wish to put a cloak over the refinery that is blocking your view of
-> the bay.”
->
-> By eliminating the effects of obstructions, such cloaking also could
-> improve wireless communications, Schurig said. Along the same
-> principles, an acoustic cloak could serve as a protective shield,
-> preventing the penetration of vibrations, sound or seismic waves.
->
-> The group’s design methodology also may find a variety of uses other
-> than cloaking, the scientists said. With appropriately fine-tuned
-> metamaterials, electromagnetic radiation at frequencies ranging from
-> visible light to electricity could be redirected at will for virtually
-> any application. For example, the theory could lead to the development
-> of metamaterials that focus light to provide a more perfect lens.
->
-> “To exploit electromagnetism, engineers use materials to control and
-> direct the field: a glass lens in a camera, a metal cage to screen
-> sensitive equipment, ‘black bodies’ of various forms to prevent unwanted
-> reflections,” the researchers said in their article. “Using the previous
-> generation of materials, design is largely a matter of choosing the
-> interface between two materials.” In the case of a camera, for example,
-> this means optimizing the shape of the lens.
->
-> The recent advent of metamaterials opens up a new range of possibilities
-> by providing electromagnetic properties that are “impossible to find in
-> nature,” the researchers said.
->
-> Their design theory provides the precise mathematical function
-> describing a metamaterial with structural details that would allow its
-> interaction with electromagnetic radiation in the manner desired. That
-> function could then guide the fabrication of metamaterials with those
-> precise characteristics, Smith explained.
->
-> The theory itself is simple, Smith said. “It’s nothing that couldn’t
-> have been done 50 or even 100 years ago,” he said.
->
-> “However, natural materials display only a limited palette of possible
-> electromagnetic properties,” he added. “The theory has only now become
-> relevant because we can make metamaterials with the properties we are
-> looking for.”
->
-> “This new design paradigm, which can provide a recipe to fit virtually
-> any electromagnetic application, leads to material specifications that
-> could be implemented only with metamaterials,” Schurig added.
->
-> The team’s next major goal is an experimental verification of
-> invisibility to electromagnetic waves at microwave frequencies, the
-> scientists said. Such a cloak, they said, would have utility for
-> wireless communications, among other applications.
