New Metamaterial Color Coatings May be Useful in the Future

When it comes to materials science, developing the latest in new coatings is important. Now, scientists have created metamaterial coatings that could be extremely useful in the future.

One of the metamaterials is one that absorbs 99.75 percent of infrared light, which is extremely useful for thermal imaging devices. Another is an ultrathin, flat lens that focuses light without imparting the distortions of conventional lenses. In fact, the scientists have created vortex beams, which are light beams that resemble a corkscrew, that could help communications companies transfer more data over limited bandwidth.

The most colorful advance to emerge is a technique that coats a metallic object with an extremely thin layer of semiconductor that's just a few nanometers thick. Although a semiconductor is a metallic, grey color, the object ends up shining in vibrant hues since the coating exploits interference effects in the thin films.

In fact, the researchers believe that the ultrathin coatings could be applied to essentially any rough or flexible material-from wearable fabrics to stretchable electronics. Because the method is unidirectional, though, the naked eye sees subtle differences in the color at different angles.

"You can imagine decorative applications where you might want something that has a bit of this pearlescent look, where you look from different angles and see a different shade," said Mikhail Kats, one of the researchers, in a news release. "But if we were to go next door and use a reactive sputterer instead of this e-beam evaporator, we could easily get a coating that forms to the surface, and you wouldn't see any differences."

The findings are published in the journal Applied Physics Letters.

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