The pattern embossed on the gold’s surface
Anodizing’s in the tech news world today because Apple (and other gadget makers) are realizing it’s a great way to make portable devices more durable and more attractive. However, the anodizing process involves coating metal with a thin layer of colored aluminum oxide: basically, it’s not changing the actual color of the metal. Researchers from the university of Southhampton in the UK announced today that they actually changed the color of gold by scuffing up its surface. It’s much more precise than that, but it does use a pattern of tiny indentations or embossments alters the way the metal absorbs and reflects light, which makes it look like different colors.
The process is called nanoembossing, and the head of the project is Nikolay Zheludev, who is the head of the nanophotonics and metamaterials at Southhampton. The coolest part is that the process can be applied to less precious metals, such as aluminum or silver. According to Zheludev, this marks the first time that the color of any metal has been changed in this way.
Currently the protoype had its patterns applied using a technique known as ion beam milling, which kind of like sandblasting at a much smaller scale. However, in the future, sheets of metal could conceivably have these pattens stamped on.
Take a look at the academic paper over at the Journal of Optics.
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