Commenced in January 2007
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Broad-Band Chiral Reflectors based on Nano-Structured Biological Materials
Abstract:In this work we study the reflection of circularly polarised light from a nano-structured biological material found in the exocuticle of scarabus beetles. This material is made of a stack of ultra-thin (~5 nm) uniaxial layers arranged in a left-handed helicoidal stack, which resonantly reflects circularly polarized light. A chirp in the layer thickness combined with a finite absorption coefficient produce a broad smooth reflectance spectrum. By comparing model calculations and electron microscopy with measured spectra we can explain our observations and quantify most relevant structural parameters.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1059895Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 777
 A.C. Neville and S. Caveney, "Scarab beetle exocuticle as an optical analogue of cholesteric liquid crystals" Biol. Rev., vol 44, pp. 531-568, 1969.
 D. J Brink, N. G. van der Berg, L. C. Prinsloo, and I.J. Hodgkinson, "Unusual coloration in scarabaeid beetles" J. Phys. D: Appl. Phys., vol 40, pp. 2189-2196, 2007.
 D. J Brink, N. G. van der Berg, and L. C. Prinsloo, "The role of interface effects on the reflection of circularly polarised light from the thin-film structure of scarabus beetles" Surf. Interface Anal., vol 40, pp. 769-771, 2008.
 I. Hodgkinson and Q. Wu, "inorganic chiral optical materials", Adv. Mater. vol 13, pp 889-897, 2001.
 K. M. Krause and M. J. Brett, "Spatially graded nanostructured chiral films as tunable circular polarizers", Ad. Funct. Mater., vol 18, pp. 3111- 3118, 2008.
 D.H. Goldstein, "Polarization properties of scarabeidae" Appl. Opt., vol 45, pp. 7944-7950, 2006.
 D. W. Berreman, "Optics in stratified anisotropic media: 4X4-matrix formulation" J. Opt. Soc. Am., vol62, pp502-510, 1972.
 R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light. Amsterdam: North Holland, 1989, pp 340-360.
 W. D. St John, W. J. Fritz, Z. J. Lu, and D. K. Yang, "Bragg reflection from cholesteric liquid crystals" Phys. Rev E, vol 51, pp. 1191-1198, 1995.
 A. L. V. Davis, D. J. Brink, C. H. Scholtz, L. C. Prinsloo, and C. M. Deshodt, "Functional implications of of temperature-correlated lolour polymorphism in an iridescent, scarabaeine dung beetle" Ecol.Entom., vol 33, pp. 771-779, 2008.