title: Optical nano-woodpiles: large-area metallic photonic crystals and metamaterials.
abstract: Metallic woodpile photonic crystals and metamaterials operating across the visible spectrum are extremely difficult to construct over large areas, because of the intricate three-dimensional nanostructures and sub-50 nm features demanded. Previous routes use electron-beam lithography or direct laser writing but widespread application is restricted by their expense and low throughput. Scalable approaches including soft lithography, colloidal self-assembly, and interference holography, produce structures limited in feature size, material durability, or geometry. By multiply stacking gold nanowire flexible gratings, we demonstrate a scalable high-fidelity approach for fabricating flexible metallic woodpile photonic crystals, with features down to 10 nm produced in bulk and at low cost. Control of stacking sequence, asymmetry, and orientation elicits great control, with visible-wavelength band-gap reflections exceeding 60%, and with strong induced chirality. Such flexible and stretchable architectures can produce metamaterials with refractive index near zero, and are easily tuned across the IR and visible ranges.
authors: NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Ave, University of Cambridge, Cambridge, CB3 0HE, UK.
authors: Lindsey A
authors: LA
authors: Ibbotson
authors: Department of Chemistry, Prince Consort Road, Imperial College London, SW7 2AZ, UK.
authors: Angela
authors: A
authors: Demetriadou
authors: Department of Materials Science and Metallurgy, University of Cambridge, UK.
authors: Stephen
authors: S
authors: Croxall
authors: The Blackett Laboratory, Department of Physics, Prince Consort Road, Imperial College, London, SW7 2AZ, UK.
authors: Ortwin
authors: O
authors: Hess
authors: NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Ave, University of Cambridge, Cambridge, CB3 0HE, UK.
authors: Jeremy J
authors: JJ
authors: Baumberg