When we last saw metamaterials, they were helping us create real-life invisibility cloaks. But, in even more exciting news for true nerds, light-bending metamaterial can also do math. Not just simple math, but calculus.

Metamaterials are artificial materials that bend light in all types of weird and unnatural ways. Scientists have now devised a theoretical metamaterial that essentially performs an instantaenous mathematical calculation as light passes through it. The material, made of ultrathin layers of aluminum-doped zinc oxide and silicon, is described in this week's issue of *Science*.

Light always bends when it passes through something—think of a pencil halfway in water—but this metamaterial bends light waves in a predictable and useful way. In tinkering with the thickness of the aluminum-doped zinc oxide and silicon layers, the researchers created a metamaterial that whose outgoing light waves match the derivative, or slope, of the light wave that went in. Taking a derivative is one of the fundamental parts of calculus.

The team's work is based on calculations of known properties, so it's still purely theoretical. But, if they do make it work, they could put it to use in computation. The metamaterial could, for example, be used for edge detection in the above photograph of Austin's skyline. It would be a lot faster than traditional computing, which has to encode the photograph into 0s and 1s first.

Invisibility cloaks are easy to get excited about, but it's just as extraordinary to imagine, someday, that window-like panes all around us are actually supercomputers doing mathematical calculations with every flicker of light. [Science via Science News, Ars Technica]

*Images courtesy of Alexandre Silva, University of Pennsylvania*

## DISCUSSION