Regensburg 2016 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 13: Nano- and microstructured dielectrics/thin films (DF with KR)
DF 13.4: Vortrag
Donnerstag, 10. März 2016, 10:30–10:50, H26
Circular dichroism of the distorted Gyroid photonic crystal — •Johannes Hielscher1, Sebastian C. Kapfer1, Caroline Pouya2, Peter Vukusic2, and Gerd E. Schröder-Turk3 — 1FAU Erlangen-Nürnberg, Institut für Theoretische Physik — 2University of Exeter, School of Physics — 3Murdoch University, School of Engineering & IT, Maths & Stats
The single Gyroid is a bi-continuous triply-periodic network with chiral I4132 cubic symmetry. When realised with two phases of dielectric contrast, it acts as a photonic crystal. As a such, it has been found in butterfly wings. Due to its chirality, it exhibits circular dichroism in reflectance.
We show that the introduction of a long-wavelength variation of the lattice constant (“sinusoidal chirp”) tunes the coupling of light waves at the interface of the photonic crystal differently depending on circular polarisation, i. e. changes the circular dichroism [1]. Reflectance spectra are gathered from numerical electrodynamics simulations, and are in good agreement with microwave optics measurements on selected 3D-printed replicas. Studying model systems, as the tetragonally distorted Gyroid and its photonic band structure, contributes to our understanding of the intricate geometrical contributions on the reflectance properties of photonic crystals, beyond the unit-cell scale.
[1] J. Hielscher; C. Pouya; P. Vukusic & G. E. Schröder-Turk: Harmonic long-range distortions of Gyroid photonic materials enhance circular dichroism. In preparation, 2016