Photonic Crystals on the Wing
Final rept. 1 Nov 2007-5 Mar 2010
GRONINGEN RIJKSUNIVERSITEIT (NETHERLANDS)
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This report results from a contract tasking University of Groningen as follows Project theme Three-dimensional 3D optical photonic crystals, periodic dielectric composite structures that forbid propagation of electromagnetic waves with a wavelength in the visible region in all directions and for any polarization, have recently entered the center stage of the optical sciences. Information and communication technology, applied coloration science, and even the cosmetics and garment industry have demonstrated a rapidly growing interest in the possibility to paint objects with structurally colored materials having precisely known spectral properties. Technical production of photonic crystals is still in its infancy, but clear demonstrations of the feasibility have recently been reported, indicating a rapidly opening research field. Nature has been experimenting already for millions of years with photonic crystals, although this has been recognized only in the last decade. The most striking examples are found among insects and birds, where brilliant, metallic colorations, produced by purely dielectric materials are widely encountered. Famous examples are the metallic-green buprestid and golden scarab beetles. The optical origin of these beautiful reflections is well understood, also owing to our recent contributions. The beetles feature stacks of multilayers with thickness of the order of 100 nm that act as interference reflectors. We have recently described similar structures in damselflies. Distinctly more complicated are the structural colors of shiny butterflies, e.g. the intense blue Morphos and the ultraviolet reflecting pierids. We nevertheless have gained a reasonable understanding also of this case. Virtually unexplored are the reflections of many butterfly and beetle species where three-dimensional architectures create highly sophisticated photonic crystals.
- Laminates and Composite Materials