Silver nanocubes used to trap light

Nature : The metamaterials used in solar panels, heat detectors, and specialized cameras absorb light efficiently, but manufacturing them is usually difficult, expensive, or both. A team led by David Smith from Duke University in Durham, North Carolina, has developed a cheap and simple alternative process to achieve a similar material. The researchers placed a thin layer of gold on a piece of glass, covered it in a layer of polymer a few nanometers thick, and then scattered silver nanocubes on the surface. When light hits the silver cubes, it excites their electrons, which create a sympathetic excitement in the electrons in the gold. The resulting “plasmon resonance” traps the light in the polymer layer; the thickness of the layer determines what wavelength of light gets trapped. Smith’s technique still needs to be refined by ensuring the silver cubes are all the same size and finding a nonorganic substitute for the polymer for use in high-temperature devices. But the ease of creating the material will likely make such metamaterials much more useful in consumer products.