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It might be small, but it’s a big feat. A lens has been built that is thinner than the waves of light it focuses. Such lenses, made from light-warping metamaterials, might someday replace the heavier glass lenses used in everything from microscopes to phone cameras.

In a normal lens, a curved glass surface a few millimetres or even centimetres thick redirects light rays to a common focal point. To improve the image – say, to take out distortions, or make sure different wavelengths of light all get focused correctly – you have to keep adding glass layers.

As a result, cameras, microscopes and telescopes are limited in part by the size and heft of the lenses they require.

“Virtual reality has the same problem,” says Reza Khorasaninejad, who designed the new lens with a team led by Federico Capasso of Harvard University. “They want to have high-resolution imaging systems, but what they will end up having is heavy helmets.”

Metamaterials, by contrast, can bend light towards a common point using structures that are as small or smaller than the wavelengths of the light waves themselves. “Our lens is flat, but I call it virtual curvature,” Khorasaninejad says.

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