Curved lenses, like those in cameras or telescopes, are stacked in order to reduce distortions and resolve a clear image — that's why telephoto lenses are so long and high-powered microscopes so big. But what if you could replace those stacks with a single flat — or planar — lens?

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have demonstrated the first planar lens that works with high efficiency within the visible spectrum of light — covering the whole range of colors from red to blue. The lens can resolve nanoscale features separated by distances smaller than the wavelength of light by using an ultra-thin array of tiny waveguides, known as a metasurface, which bends light as it passes through. This lens could replace stacks of lenses in everything from cell phones to cameras, microscopes and telescopes.

Learn more about it here