"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.
Duke Pratt School of Engineering
marketing@alchempro.com
