Single metalens focuses the entire visible spectrum of light to one point

Metalenses — flat surfaces that use nanostructures to focus light — have promised to revolutionize optics by replacing the bulky, curved lenses currently used in optical devices with a simple, flat surface, but previously metalenses had been limited in the spectrum of light they could focus well. Now a team of researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has developed the first single lens that can focus the entire visible spectrum — including white light — in the same spot and in high resolution, a feat previously achieved only by stacking multiple conventional lenses.