Optically-ambidextrous circularly-polarised reflection from the chiral cuticle of the scarab beetle Chrysina resplendens
Finlayson, Ewan D.; McDonald, Luke T.; Vukusic, Pete
Date: 14 June 2017
Journal
Interface
Publisher
Royal Society
Publisher DOI
Abstract
The evolution of structural colour mechanisms in biological
systems has given rise to many interesting optical effects in
animals and plants. The instance of the scarab beetle Chrysina
resplendens is particularly distinctive. Its exoskeleton has a
bright, golden appearance and reflects both right-handed and
left-handed ...
The evolution of structural colour mechanisms in biological
systems has given rise to many interesting optical effects in
animals and plants. The instance of the scarab beetle Chrysina
resplendens is particularly distinctive. Its exoskeleton has a
bright, golden appearance and reflects both right-handed and
left-handed circularly-polarized light concurrently. The chiral
nanostructure responsible for these properties is a helicoid, in
which birefringent dielectric planes are assembled with an
incremental rotation. This study correlates details of the
beetle’s circularly-polarized reflectance spectra directly with
physical aspects of its structural morphology. Electron
micrography is used to identify and measure the physical
dimensions of the key constituent components. These include
a chiral multilayer configuration comprising two chirped, lefthanded
helicoids that are separated by a birefringent retarder.
A scattering matrix technique is used to simulate the system’s
optical behaviour in which the roles of each component of the
morphological substructure are elucidated by calculation of
the fields throughout its depth.
Physics and Astronomy
Faculty of Environment, Science and Economy
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