Single metalens focuses all colors of the rainbow in one point

Metalenses — flat surfaces that use nanostructures to focus light — promise to revolutionize optics by replacing the bulky, curved lenses currently used in optical devices with a simple, flat surface. But, these metalenses have remained limited in the spectrum of light they can focus well. Now a team of researchers has developed the first single lens that can focus the entire visible spectrum of light — including white light — in the same spot and in high resolution.