%0 Journal Article %A D.J. Brink and N.G. van der Berg and L.C. Prinsloo and A. Botha %D 2009 %J International Journal of Physical and Mathematical Sciences %B World Academy of Science, Engineering and Technology %I Open Science Index 33, 2009 %T Broad-Band Chiral Reflectors based on Nano-Structured Biological Materials %U https://publications.waset.org/pdf/4809 %V 33 %X 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. %P 603 - 607