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The role of interface effects on the reflection of circularly polarised light from the thin‐film structure of scarabus beetles
Author(s) -
Brink D. J.,
van der Berg N. G.,
Prinsloo L. C.
Publication year - 2008
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.2639
Subject(s) - stack (abstract data type) , reflection (computer programming) , iridescence , optics , rotation (mathematics) , layer (electronics) , thin film , materials science , structural coloration , resonance (particle physics) , reflectivity , spectral line , molecular physics , physics , condensed matter physics , geometry , atomic physics , photonic crystal , nanotechnology , mathematics , computer science , astronomy , programming language
Many scarabus beetles, such as Gymnopleurus virens exhibit exceptionally bright iridescent colours caused by a Bragg resonance in the thin‐layered structure of the exocuticle. These layers are rotated by a small angle with respect to each other resulting in a helcoidal stack, which reflects circularly polarised light with the same sense of rotation as that of the stack. Previous work assumed a smooth chiral structure, but in this work we explicitly include the effect of discrete layers and twist angles and investigate the effect of different layer densities on the reflectance spectrum. By comparing modelled results to experimentally recorded spectra it is possible to estimate the actual layer density found in this scarabus beetle. Copyright © 2008 John Wiley & Sons, Ltd.