Tuesday, August 14, 2007

Levitating Nanomachines

Continued from page 1

By Prachi Patel-Predd

According to Umar Mohideen, a physics professor at the University of California, Riverside, who was one of the first to measure the Casimir force accurately, "Anything that can tailor the [Casimir] force is useful from an engineering point of view, since the force is such a big parameter." But making the perfect lenses will not be easy, he cautions, because the technology is new and still faces many challenges.

Perfect lenses have to be painstakingly designed and fabricated to work with specific wavelengths of light. Only within the past year have researchers designed perfect lenses that work at wavelengths as small as a micrometer, Mohideen says. To reverse the Casimir force in a NEMS device, a perfect lens will have to work at even shorter wavelengths--that is, those corresponding to the nanometer distances between parts. Designing and manufacturing such a lens is not a trivial task, says Jordan Maclay, chief scientist at Quantum Fields, based in Richland Center, WI. Controlling the spacing between the lens and the parts of a NEMS device will also be a challenge, Maclay says.

Making perfect lenses with the right properties could take years. And once those lenses are in hand, says Mohideen, researchers will still face the challenge of doing experiments to verify the new theory. But so far, using perfect lenses is the only technique proposed to reverse the Casimir force, Decca says. The promise of frictionless nanosensors and switches might make the method worth testing.