liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Polarization properties and structural color of the scarab beetle Cotinis mutabilis (Mayatl)
Cinvestav-Unidad Queretaro, Mexico.
Cinvestav-Queretaro, Mexico.
(Cinvestav-Queretaro, Mexico)
Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
Show others and affiliations
2012 (English)Conference paper, Poster (Other academic)
Abstract [en]

Nature offers a plethora of possibilities for optical biomimetics. Some birds, butterflies, insects and other creatures exhibit brilliant colors as result of diverse optical phenomena produced by micro- and nanostructures at the near surface. Particularly, the shiny metallic colors reflected by the exoskeleton (the so called cuticle) of some beetles show elliptical polarization properties; most commonly of the left-handed type but also the right-handed type has been found [1]. These color and polarization properties have been related to a twisted plywood or Bouligand structure which is comprised by the clustering of chitin nanofibrils wrapped by proteins in a planar woven.

In this work we report the polarization properties of light reflected from the scarab beetle Cotinis mutabilis (Gory and Percheron 1833) and the microstructure of its cuticle. This species is found in Mexico and the southwestern part of the United States. The specimen under study was collected at the facilities of Cinvestav in Querétaro, Mexico where it is known as mayate (Mayatl in Náuhtl, the language of Aztecs). The Mayatl presents a green mate color in its dorsal side with red-orange stripes in the elytra. On the other hand, the abdominal side shows a shiny green metallic color which is subject of the present study. The polarization properties are investigated by the complete Mueller matrix (M) measured with a dual rotating compensator ellipsometer (J. A. Woollam Co., Inc.) at angles of incidence of 20-75° and wavelength range of 250-1000 nm. In particular, the elements m41 and m14 of M show that green left-handed polarized light is reflected when the beetle is illuminated at near-normal angles of incidence with unpolarized white light. As the angle of incidence increases the maximum of light reflected is blue-shifted. The degree of polarization, ellipticity, and azimuth calculated with relationships between mj1 elements provide a full description of the polarization state of light reflected from the beetle’s cuticle for incident un-polarized light. Scanning electron microscopy images of the cuticle reveal that the epicuticle and exocuticle comprise a (hard) layer ca. 15 μm thick. Two regions can be differentiated in the exocuticle: the outer exocuticle without any clear structure and the inner exocuticle where a clear multilayer structure is observed. Beneath the inner exocuticle is the endocuticle which is comprised by unidirectional layers of microfibrils alternate with layers running at nearly right angles to each other in a pseudo-orthogonal arrangement. The cuticle also was imaged with a microscope coupled to a FTIR system allowing further identification of bands due to chitin.

Place, publisher, year, edition, pages
Keyword [en]
Mueller-matrix ellipsometry; scarab beetles; natural nanostructures; circular polarization
National Category
Physical Sciences
URN: urn:nbn:se:liu:diva-86674OAI: diva2:579991
XXI International Materials Research Congress (IMRC 2012), August 12 - 17, 2012, Cancun, Mexico
Available from: 2012-12-20 Created: 2012-12-20 Last updated: 2013-10-14

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Landin, JanJärrendahl, KennethArwin, Hans
By organisation
Applied Optics The Institute of Technology
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 158 hits
ReferencesLink to record
Permanent link

Direct link