86 research outputs found
Optical structure and function of the white filamentary hair covering the edelweiss bracts
The optical properties of the inflorescence of the high-altitude
''Leontopodium nivale'' subsp. ''alpinum'' (edelweiss) is investigated, in
relation with its submicrometer structure, as determined by scanning electron
microscopy. The filaments forming the hair layer have been found to exhibit an
internal structure which may be one of the few examples of a photonic structure
found in a plant. Measurements of light transmission through a self-supported
layer of hair pads taken from the bracts supports the idea that the wooly layer
covering the plant absorbs near-ultraviolet radiation before it reaches the
cellular tissue. Calculations based on a photonic-crystal model provides
insight on the way radiation can be absorbed by the filamentary threads.Comment: 9 pages, 13 figures. Published pape
Theoretical approach of bistability in nonlinear optical structures involving photonic crystals
Etude théorique des phénomènes de bistabilité dans les structures optiques non linéaires intégrant des cristaux photoniques
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