October 22, 2009

Waves trapped in maze-like grooves

The icons depict the shape of the energy-trapping ridges on the disc at the center and the edges - via arXiv.org

It's not really a pocket black hole, despite the headlines- it doesn't attract mass, and when it says light in the following quote what it really means is microwave frequencies of electromagnetic radiation, not actual visible light:
....this simple metal disc uses the geometry of 60 concentric rings of meta-materials to lock up light for good. The meta-material "resonators" that make up the rings affect the magnetic properties of passing light, bending the beams into the center of the disc, and trapping them in the etched maze-like grooves.

It is made of 60 annular strips of so-called "meta-materials", which have previously been used to make invisibility cloaks. Each strip takes the form of a circuit board etched with intricate structures whose characteristics change progressively from one strip to the next, so that the permittivity varies smoothly. The outer 40 strips make up the shell and the inner 20 strips make up the absorber.
Fabricating a device that captures optical wavelengths in the same way will not be easy, as visible light has a wavelength orders of magnitude smaller than that of microwave radiation. This will require the etched structures to be correspondingly smaller

Cui is confident that they can do it. "I expect that our demonstration of the optical black hole will be available by the end of 2009," he says.

Such a device could be used to harvest solar energy in places where the light is too diffuse for mirrors to concentrate it onto a solar cell. An optical black hole would suck it all in and direct it at a solar cell sitting at the core. "If that works, you will no longer require these huge parabolic mirrors to collect light," says Evgenii Narimanov [who, with Alexander Kildishev, both of Purdue University, came up with the idea behind the design].
It was made in China and looks like an old coin, nothing special, but to someone like me, who doesn't quite get the device or it's implications, it's full of ancient cool. Exactly what you'd want from a piece of alien tech.

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