Rare is the moment when Harry Potter fans, Star Trek aficionados, H. G. Wells enthusiasts, and theoretical physicists unite in a moment of ecstasy. But that instant came last May with a flurry of dramatic headlines. "Scientists may be able to make magic like Harry Potter," wrote the Associated Press. "Here's how to make an invisibility cloak," shouted MSNBC. "Cast no shadows," said The Economist. For Duke University physicist David Smith, though, the oddest moment was seeing his work flashed on the CNN crawl the same day it appeared in Science Express, the online edition of the journal Science. "It was surreal," he says. "The story was generating a huge splash before the scientific community had a chance to take a critical look."
Smith hardly fits the profile of a media celebrity: soft-spoken, patient, and bespectacled, he has the pale-skinned hue of a man who has perhaps spent too much time in a windowless lab fiddling with wires. All at once, however, he and his postdoc Dave Schurig became the targets of intense public interest. Reporters called from around the world, crackpots sent long letters hand-scrawled with dubious hypotheses, and a Korean television crew flew in to the leafy Duke campus, posing Schurig, graduate student Jonah Gollub, and technician Bryan Justice in lab coats in front of their intricate machinery. "They wouldn't film until we put the white coats on. We didn't even have any—we had to borrow them," recalls Schurig.
All this fuss over a theory not only unproved but so dense with equations it is all but incomprehensible to the average person. What sparked such fascination was the mind-bending notion itself: Smith, Schurig, and their coauthor John Pendry of Imperial College London proposed that by using a novel class of composite materials, they could manipulate light so as to render an object invisible to the eye. Suddenly, Harry Potter's invisibility cloak, Star Trek's Romulan ship-concealing devices, and H. G. Wells's bandaged Invisible Man seemed the stuff of testable science. In a more practical vein, the finding could have profound implications for military technology, wireless communication, and even interplanetary exploration.
In September, the journal Science accepted a paper from Smith and Schurig that proved that their method was more than just a thrilling hypothesis. They had succeeded in cloaking a small cylindrical object—shielding it not from visible light but from microwaves, a form of electromagnetic radiation with a substantially longer wavelength, which makes the cloaking effect considerably easier to achieve. The way they did it most closely recalls not Harry Potter but another fictional character: the Invisible Woman, a Marvel Comics superhero who can bend light waves at her command, rendering her body and clothing imperceptible. By tightly controlling the bending, or refraction, of microwaves as they pass through a custom-built material, the Duke researchers could force them to detour around an object so that the microwaves are neither absorbed nor reflected. If they performed the same feat with visible light, a viewer looking directly at the object would see only what lies behind it, as if the object were not even there.
