An artistic rendition of how the new ultrafast metasurface works. Mikkelsen’s lab’s approach, called a “metasurface,” uses precisely tailored silver nanocubes placed on a transparent film only 10 nanometers above a thin layer of gold. When light strikes the surface of a nanocube, it excites the silver’s electrons, trapping the light’s energy through a phenomenon known as plasmonics—but only at a specific frequency controlled by the nanocubes’ sizes and spacings. Credit: Duke University