Berlin 2012 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 11: Optical and nonlinear optical properties, photonic
DF 11.7: Vortrag
Mittwoch, 28. März 2012, 11:40–12:00, EB 107
Circular Dichroism in Biological Photonic Crystals — •Matthias Saba1, Michael Thiel2, Mark Turner3, Klaus Mecke1, and Gerd Schröder-Turk1 — 1Theoretische Physik, Universität Erlangen, 91058 Erlangen, Germany — 2Angewandte Physik & Center for Functional Nanostructures, KIT, 76128 Karlsruhe, Germany — 3Centre for Micro-Photonics & CUDOS, Swinburne University of Technology, VIC 3122, Australia
We introduce a chirality index that measures the circular dichroism of chiral photonic crystals by quantifying the degree of circular polarisation of the photonic band structure eigenmodes [1]. Nature provides a variety of examples for structural color in bird feathers, beetle shells and butterfly wings. It is widely accepted that the green color of the butterfly callophrys Rubi is caused by the nanostructure of its chitin wing-scales. This structure is modelled by a Gyroid constant mean curvature body and acts as a photonic crystal [2]. Our method, backed up by an alternative numerical transmission calculation based on a scattering matrix approach, reveals strong circular dichroism of the chiral Gyroid photonic crystal in the near UV. This response is a remarkable finding for a photonic crystal made of air and chitin with a low dielectric contrast and suggests technological designs [3] as well as possible relevance for butterfly communication.
[1] M. Saba et al., Phys. Rev. Lett. 106, 103902 (2011)
[2] G.E. Schröder-Turk et al., J. Struct. Biol. 174(2), 290 (2011)
[3] M. D. Turner et al., Opt. Express 19, 10001 (2011).