16 January 2009
Researchers show off next generation cloaking device
by Kate Melville
Duke University engineers have produced a new type of cloaking device which is significantly more sophisticated at cloaking in a broad range of frequencies. The latest advance was made possible by the development of a new series of algorithms to guide the design and fabrication of exotic composite materials known as metamaterials.
[Pictured is researcher David R. Smith with the new metamaterial cloaking a bump]
Metamaterials can be engineered to have properties not normally found in natural materials. Such exotic constructs can guide electromagnetic waves around an object, to have them emerge on the other side as if they had passed through an empty volume of space.
The results of the latest Duke experiments were published in the journal Science and according to the research team, the new algorithm will make it possible to custom-design unique metamaterials with specific cloaking characteristics much more quickly than was previously possible.
"The new device can cloak a much wider spectrum of waves - nearly limitless - and will scale far more easily to infrared and visible light. The approach we used should help us expand and improve our abilities to cloak different types of waves," said Duke's David R. Smith.
Smith believes that cloaks should find numerous applications as the technology is perfected. By eliminating the effects of obstructions, cloaking devices could improve wireless communications, or acoustic cloaks could serve as protective shields, preventing the penetration of vibrations, sound or seismic waves.
Commenting on the demonstration cloaking application, co-researcher Ruopeng Liu said that "the ability of the cloak to hide the bump is compelling. Though the designs of such metamaterials are extremely complex, especially when traditional approaches are used, we believe that we now have a way to rapidly and efficiently produce such materials."
The newest cloak, which measures 20 inches by 4 inches and less than an inch high, is actually made up of more than 10,000 individual pieces arranged in parallel rows. Of those pieces, more than 6,000 are unique. Each piece is made of the same fiberglass material used in circuit boards and etched with copper. The new algorithm determined the shape and placement of each piece.
Source: Duke University