Metalenses are finally moving into consumers’ hands
Inside today’s computers, phones, and other mobile devices, more and more sensors, processors, and other electronics are fighting for space. Taking up a big part of this valuable real estate are the cameras—just about every gadget needs a camera, or two, three, or more. And the most space-consuming part of the camera is the lens.
The lenses in our mobile devices typically collect and direct incoming light by refraction, using a curve in a transparent material, usually plastic, to bend the rays. So these lenses can’t shrink much more than they already have: To make a camera small, the lens must have a short focal length; but the shorter the focal length, the greater the curvature and therefore the thickness at the center. These highly curved lenses also suffer from all sorts of aberrations, so camera-module manufacturers use multiple lenses to compensate, adding to the camera’s bulk.
With today’s lenses, the size of the camera and image quality are pulling in different directions. The only way to make lenses smaller and better is to replace refractive lenses with a different technology.
That technology exists. It’s the metalens, a device developed at Harvard and commercialized at Metalenz, where I am an applications engineer. We create these devices using traditional semiconductor-processing techniques to build nanostructures onto a flat surface. These nanostructures use a phenomenon called metasurface optics to direct and focus light. These lenses can be extremely thin—a few hundred micrometers thick, about twice the thickness of a human hair. And we can combine the functionality of multiple curved lenses into just one of our devices, further addressing the space crunch and opening up the possibility of new uses for cameras in mobile devices.
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