Researchers developed a new ultra-thin planar (flat) "metalens" that can potentially replace the stacked, bulky lenses used in telescopes, microscopes, smartphones, cameras and other gadgets.

Despite the many advancements in lens technology, there are no commercially available lenses today that can replace the stacked ones with a single flat compact-thin lens.

Today's curved lenses, like the ones used in telescopes and cameras, are stacked on top of each other to lower image distortions and produce a clear image. This explains why telephoto lenses are so long while powerful microscope lenses are so big.

A research team from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) developed the first planar lens. The new flat lens is highly efficient within the light's visible spectrum.

The new planar lens is also capable of resolving nanoscale features. A very thin assembly of minuscule waveguides called "metasurface" bends the passing light. The process is similar to that of today's curved lens.

For the lens, they used titanium dioxide to create the metalens' heart — the nanoscale collection of high-aspect ratio and smooth nanostructures.

The metalens' heart is capable of providing better focus compared to today's best-in-class commercial lenses.

According to senior author Federico Capasso, the new lens technology has the potential to become a revolutionary product. The capacity to work in the light's visible spectrum suggests it can replace the current lenses used in all types of devices.

"In the near future, metalenses will be manufactured on a large scale at a small fraction of the cost of conventional lenses, using the foundries that mass produce microprocessors and memory chips," said Capasso, who is a Robert L. Wallace professor of Applied Physics.

The study authors already filed patents for the new metalens. They are also in the process of looking for commercial opportunities for the world's first planar lenses.

"But our lenses, being planar, can be fabricated in the same foundries that make computer chips. So all of a sudden the factories that make integrated circuits can make our lenses," added Capasso.

The research was published in the Science journal on June 3.

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