February 21, 2008

Blackest black

From the Washington Post, heavily edited by me:

Researchers in New York reported this month that they have created a paper-thin material that absorbs 99.955 percent of the light that hits it, making it by far the darkest substance ever made......It is made of carbon nanotubes: microscopic, hollow fibers whose walls are just one atom thick. Importantly, the fibers are widely spaced, providing plenty of space to allow light in and almost no surfaces to bounce it back out....By voraciously sucking up all surrounding illumination, it can give those who gaze on it a dizzying sensation of nothingness.

[In addition a] nascent invisibility cloak now being tested is made of a material that bends light rays "backward," a weird phenomenon thought to be impossible just a few years ago.

Known as transformation optics, the phenomenon compels some wavelengths of light to flow around an object like water around a stone. As a result, things behind the object become visible while the object itself disappears from view.

Professor Pendry pioneered much of modern thinking about how to attain full invisibility using "metamaterials" -- substances engineered to manhandle light. Ordinary matter, such as glass or water, slows and bends light as it passes through. Metamaterials contain bits of metal or other substances embedded in precise patterns to make the light bend in an opposite direction from normal paths.

"In a sense you have some negative space," Pendry said. "The light appears to go backward."

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