Exploring polarization features in light reflection from beetles with structural colors
2015 (English)In: Proc. SPIE 9429, Bioinspiration, Biomimetics, and Bioreplication 2015, SPIE - International Society for Optical Engineering, 2015, Vol. 9429, 942909-1-942909-13 p.Conference paper (Refereed)
A Mueller matrix of a sample can be used to determine the polarization of reflected light for incident light with arbitrary polarization. The polarization can be quantified in terms of ellipticity, polarization azimuth and degree of polarization. We apply spectroscopic Mueller-matrix ellipsometry at multiple angles of incidence to study the cuticle of beetles and derive polarization features for incident unpolarized light. In particular we address chiral phenomena in scarab beetles, the origin of their structural colors and the observed high degree of circular polarization is discussed. Results from beetles in the Scarabaeidae subfamilies Cetoniinae and Rutelinae are presented including specimens with broad-band silver- or gold-like colors with metallic shine as well as specimens with narrow-band green or red reflectors. The variation of polarization with angle of incidence and occurrence of both left-handed and right-handed polarization from a single species are presented. We also use Mueller-matrix spectra in electromagnetic modeling and show how to determine structural parameters including cuticle layer thicknesses and optical properties. Interference oscillations in the observed spectra are due to allowed optical modes and we show how to develop a structural model of a cuticle based on this effect. Sum decomposition of Mueller matrices measured on a depolarizing cuticle of a beetle is briefly discussed.
Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2015. Vol. 9429, 942909-1-942909-13 p.
, Proceedings of SPIE, ISSN 0277-786X ; 9429
Mueller-matrix ellipsometry; chiral reflectors; circular polarization; beetle cuticle
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:liu:diva-116701DOI: 10.1117/12.2083032ISI: 000357257400002ISBN: 978-1-62841-532-2OAI: oai:DiVA.org:liu-116701DiVA: diva2:800022
SPIE: smart structures NDE Bioinspiration, Biomimetics, and Bioreplication 2015
FunderSwedish Research Council, 621-2011-4283Carl Tryggers foundation , CTS12:31Knut and Alice Wallenberg Foundation