'Left-Handed' Material Said to Reverse Energy
By Joel Achenbach
The materials, described as "left-handed," reverse the normal way that microwave energy--including such standard natural phenomena as the Doppler Effect--behaves, the researchers said.
"This is Alice in Wonderland. The effects get curiouser and curiouser as we go through them," said Sheldon Schultz, who with his colleague David R. Smith, both of the University of California at San Diego, spoke to reporters here at a national meeting of the American Physical Society.
The researchers displayed a sample of the new "meta-material," and it appeared to be something that any tinkerer might hammer together in a basement. The scientists mounted studs of copper wire on a metal plate and interlaced them with thin strips of copper rings, everything held snug with strips of Styrofoam. The sample could easily be held in one hand. The innovation is not in the raw materials, but in their arrangement. When microwaves are beamed through the material they become focused rather than diverging, as they normally would, the researchers said.
It is the combination of the specially designed copper rings arranged against the copper wires that gives the material the property of reversing the normal response to energy, the researchers said.
"If these effects turn out to be possible at optical frequencies, this material would have the crazy property that a flashlight shining on a slab can focus the light at a point on the other side. There's no way you can do that with just a sheet of ordinary material," Schultz said.
Three physicists with no connection to the research who attended the presentation agreed that it was an exciting development. The materials obey all the normal laws of physics, they said.
"It's not backwards in time. It's not making you younger. It's not science fiction. It's not spooky," Schultz said. "It opens up a class of materials that just have not been available."
Their paper describing the advance--"A Composite Medium with Simultaneously Negative Permeability and Permittivity"--will be published soon in the journal Physical Review Letters.
The paper written by the scientists was initially rejected without review by Physical Review Letters. The scientists blamed their inability to explain the significance of the work. Then Smith, combing through scientific papers on "negative permeability," came across an obscure paper from 1968 written by a Russian theorist, V.G. Veselago. Veselago predicted that a material with electric and magnetic response to electromagnetic radiation that is the opposite to the norm, if such a thing were ever found or invented, would reverse the manner in which the energy traveled through it. "We didn't understand there was anything special about it until I found that paper," Smith said.
>From Veselago, Smith picked up the term "left-handed." Smith and Schultz and three colleagues at UCSD then elaborated on their description of their work in the original paper and this time got it reviewed and approved by three anonymous experts.
Smith said he found out only early this week that Veselago is still alive. "He said in some sense he had written it off as a joke, because he didn't think it would ever be realized," Smith said.
Schultz, 67, said it was the most important development in his 39-year career. Smith, 35, said his team filed for a patent only this past Friday. The research is clearly competitive: The scientists acknowledged a debt to a British physicist, John Pendry of Imperial College, London, who in 1996 had described a way to use ordinary copper wires to create a material with certain left-handed qualities. The California scientists said they believed Pendry is also seeking patent rights for materials he has produced.
The scientists were quick to acknowledge that the research is in the early stages and that they don't yet know what may come of the discovery. Since they have shown that the materials have a dramatic effect on microwave propagation, they assume it might be used in the wireless communication industry--for example, in the construction of antennas.
"Don't ask me to predict the next whiz-bang left-handed materials
company," Schultz said.
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