Brilliant whiteness in ultrathin beetle scales.

The colored appearances of animals are controlled by pigmentation, highly periodic ultrastructure, or a combination of both. Whiteness, however, is less common and is generated by neither of these, because it requires scattering processes appropriate for all visible wavelengths. We report whiteness resulting from a three-dimensional photonic solid in the scales of Cyphochilus spp. beetles. Their scales are characterized by their exceptional whiteness, their perceived brightness, and their optical brilliance, but they are only 5 micrometers thick. This thickness is at least two orders of magnitude thinner than common synthetic systems designed for equivalent-quality whiteness.