Interplay of index contrast with periodicity in polymer photonic crystals

We report how the strength of resonant Bragg reflection from polymeric photonic crystals (polymer opals) varies linearly with the refractive-index contrast, Δn , in contrast to the quadratic buildup of Fresnel reflections scaling as ( Δn ) 2 . This occurs due to the interplay of disorder and periodi...

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Bibliographic Details
Published in:Applied physics letters 2011-12, Vol.99 (26), p.261913-261913-4
Main Authors: Finlayson, Chris E., Haines, Andrew I., Snoswell, David R. E., Kontogeorgos, Andreas, Vignolini, Silvia, Baumberg, Jeremy J., Spahn, Peter, Peter Hellmann, G.
Format: Article
Language:English
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Summary:We report how the strength of resonant Bragg reflection from polymeric photonic crystals (polymer opals) varies linearly with the refractive-index contrast, Δn , in contrast to the quadratic buildup of Fresnel reflections scaling as ( Δn ) 2 . This occurs due to the interplay of disorder and periodicity, in agreement with a simple 1-dimensional periodic model. Goniometry experiments show that opal films exhibit "cones" of resonantly scattered light, which extend to ±20° angular deviation from the specular direction. The intensity of the scattering cones varies super-linearly with Δn . Such medium contrast photonic crystals are of significant interest for understanding structural colors exhibited in nature, by structures with inherent disorder.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.3672215