title: Antireflection-enhanced color by a natural graded refractive index (GRIN) structure.
abstract: Nanostructured materials like graded refractive index (GRIN) structures in moth eyes have inspired the design of novel antireflective coatings. Such structures are more flexible than uniform coatings, but applications have been mainly limited to broadband antireflection in solar cells and LEDs. Here we show that cylindrical pigment granules in two bird species (Polyplectron bicalcaratum and Patagioenas fasciata) form a GRIN that suppresses interference and expands the range of colors produced by a multilayer. These results demonstrate that a GRIN structure can function like a pigment (i.e. through selective, independent wavelength blocking) to generate unique colors and may inspire the design of novel antireflective and structurally colored coatings.
authors.forename: Chad M
authors.initials: CM
authors.lastname: Eliason
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Shawkey