Thursday, February 21, 2008

Transformation Optics

I tried to watch the full moon go black last night, but it was too cloudy. Lunar eclipses are always worth the effort. I think I've seen a half dozen or so in my lifetime. The next one for us is in 2010.

Speaking of going black, in my wardrobe of black shirts, socks, pants, and shoes, I have a black T shirt that says, "I'm only wearing black until they make something darker."

Well, they have. And it fits right in to the solid state materials revolution that I wrote about two days ago.

Here is part of the story from the Post:

Their Deepest, Darkest Discovery
Scientists Create a Black That Erases Virtually All Light
By Rick WeissWashington Post Staff Writer
Wednesday, February 20, 2008;

Black is getting blacker

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 -- about 30 times as dark as the government's current standard for blackest black.

The material, made of hollow fibers, is a Roach Motel for photons -- light checks in, but it never checks out. By voraciously sucking up all surrounding illumination, it can give those who gaze on it a dizzying sensation of nothingness.

"It's very deep, like in a forest on the darkest night," said Shawn-Yu Lin, a scientist who helped create the material at Rensselaer Polytechnic Institute in Troy, N.Y. "Nothing comes back to you. It's very, very, very dark."

But scientists are not satisfied. Using other new materials, some are trying to manufacture rudimentary Harry Potter-like cloaks that make objects inside of them literally invisible under the right conditions -- the pinnacle of stealthy technology.

Both advances reflect researchers' growing ability to manipulate light, the fleetest and most evanescent of nature's offerings. The nascent invisibility cloak now being tested, for example, 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.

"Cloaking is just the tip of the iceberg," said Vladimir Shalaev, a professor of electrical and computer engineering at Purdue University and an expert in the fledgling field. "With transformation optics you can do many other tricks," perhaps including making things appear to be located where they are not and focusing massive amounts of energy on microscopic spots." (clip)

While Lin and his colleagues, including Pulickel Ajayan, now at Rice University, pursue applications for their superblack, Pendry and others are hoping to go further by perfecting complete invisibility. The big difference is that a superblack object, even if invisible to the eye, still casts a shadow behind it, while an object shielded by an invisibility cloak does not.

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 in space." clip

There is a flip side to the emerging ability to manipulate light, scientists say. "Think anti-cloaking," said Shalaev, the engineering professor. "Instead of excluding light from an object, you can concentrate light in a small area."

Normally, light cannot be squeezed into a space smaller than its own wavelength, he said, but transformation optics create the possibility of accomplishing just that -- packing loads of energy into a vanishingly small space." more

Will this development have implications in the creation of a photonic energy web?


Some solar companies such as SolFocus of Mountain View California., are already in touch with Lin. Regular old fashion solar hot water heaters will become more efficient with these materials, but there are some really intriguing possibilities here that will apply in the world of advanced Photonic devices and advanced focusing strategies.

Transformation Optics and the other advancing sciences of light and advanced materials have the potential to change our lives and the very way we see the universe.

And maybe, just maybe, they will even

transform us.



Anonymous Anonymous said...

There are usually two lunar eclipses each year somewhere on earth. 2009 has four, two of which are visible in the Americas but none of which are total. You are right that the next total lunar eclipse visible in Texas will be on 21 Dec 2010. Lots more info is at
El Gringo

11:19 AM  
Anonymous Anonymous said...

Earthfamilyalpha always blows my mind - amazing, amazing technologies! Don't know how you discover what the scientific maverics are doing, but thank you.


2:55 PM  

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