05 June 2008

A Tale of Two Nano-Arrays

The nano-array pictured above is described as a perfect absorber of light--it reflects none of the incident light, instead turning all radiant energy into heat.
"Three things can happen to light when it hits a material," says Boston College Physicist Willie J. Padilla. "It can be reflected, as in a mirror. It can be transmitted, as with window glass. Or it can be absorbed and turned into heat. This metamaterial has been engineered to ensure that all light is neither reflected nor transmitted, but is turned completely into heat and absorbed. It shows we can design a metamaterial so that at a specific frequency it can absorb all of the photons that fall onto its surface."

...Because its elements can separately absorb the electric and magnetic components of an electromagnetic wave, the "perfect metamaterial absorber" created by the researchers can be highly absorptive over a narrow frequency range.

The metamaterial is the first to demonstrate perfect absorption and unlike conventional absorbers it is constructed solely out of metallic elements, giving the material greater flexibility for applications related to the collection and detection of light, such as imaging, says Padilla, an assistant professor of physics.

Metamaterial designs give them new properties beyond the limits of their actual physical components and allow them to produce "tailored" responses to radiation. Because their construction makes them geometrically scalable, metamaterials are able to operate across a significant portion of the electromagnetic spectrum. __RDMag__via_NEN

The nano-array above was previously discussed here at Al Fin and at New Energy and Fuel. This second array was designed to capture the radiative energy of light and turn it into electrical energy. Compare the two arrays at your leisure and note the similarities and differences. Both nano-arrays can be optimised for particular ranges of photon wavelength.

The potential range of applications for these arrays, and similar "metamaterials" made from precise nano-configuration of ordinary matter, is immense. These nano-arrays are something new under the sun, and worth considering.

Our planet is constantly bathed by showers of photons, and other particles from the sun. Until recently, humans have used the sun for agriculture, tanning, and heating, and inadvertently for Vitamin D production. It is long past time for us to begin using the sun, and other sources of infrared radiation, more thoroughly.

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