title: Circular dichroism in biological photonic crystals and cubic chiral nets.
abstract: Nature provides impressive examples of chiral photonic crystals, with the notable example of the cubic so-called srs network (the label for the chiral degree-three network modeled on SrSi2) or gyroid structure realized in wing scales of several butterfly species. By a circular polarization analysis of the band structure of such networks, we demonstrate strong circular dichroism effects: The butterfly srs microstructure, of cubic I4(1)32 symmetry, shows significant circular dichroism for blue to ultraviolet light, that warrants a search for biological receptors sensitive to circular polarization. A derived synthetic structure based on four like-handed silicon srs nets exhibits a large circular polarization stop band of a width exceeding 30%. These findings offer design principles for chiral photonic devices.
authors.affiliation: Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Saba
authors.forename: M
authors.initials: M
authors.lastname: Thiel
authors.forename: M D
authors.initials: MD
authors.lastname: Turner
authors.forename: S T
authors.initials: ST
authors.lastname: Hyde
authors.forename: M
authors.initials: M
authors.lastname: Gu
authors.forename: K
authors.initials: K
authors.lastname: Grosse-Brauckmann
authors.forename: D N
authors.initials: DN
authors.lastname: Neshev
authors.forename: K
authors.initials: K
authors.lastname: Mecke
authors.forename: G E
authors.initials: GE
authors.lastname: Schröder-Turk
mesh_terms: D000818:Animals; D002080:Butterflies / Q000648:ultrastructure; D002942:Circular Dichroism; D003460:Crystallization; D017785:Photons; D014921:Wings, Animal / Q000033:anatomy & histology* / Q000648:ultrastructure