title: Measuring and modelling the reflectance spectra of male Swinhoe's pheasant feather barbules.
abstract: A range of iridescent colour appearances are presented by male Swinhoe's pheasants' (Lophura swinhoii) mantle feathers. Two distinct regions of the open pennaceous portion of its feathers display particularly conspicuous angle-dependent reflection. A bright blue band appears in one region at normal incidence that spatially shifts to another at higher illumination angles. The two-dimensional photonic crystal-like nanostructures inside the barbules of these two regions are similar. However, this study found that the spatial variation in their colour appearance results from a continuously changing orientation of barbules with respect to the alignment of their associated barb. A multi-layered rigorous coupled-wave analysis approach was used to model the reflections from the identified intra-barbule structures. Well-matched simulated and measured reflectance spectra, at both normal and oblique incidence, support our elucidation of the origin of the bird's distinctive feather colour appearance.
authors: Department of Optics and Photonics, National Central University, Chung-Li, Taiwan Thin Film Technology Center, National Central University, Chung-Li, Taiwan cclee@dop.ncu.edu.tw.
authors: Cheng-Chung
authors: CC
authors: Lee
authors: Department of Optics and Photonics, National Central University, Chung-Li, Taiwan Thin Film Technology Center, National Central University, Chung-Li, Taiwan.
authors: Shih-Fang
authors: SF
authors: Liao
authors: School of Physics, University of Exeter, Exeter, UK p.vukusic@exeter.ac.uk.
authors: Pete
authors: P
authors: Vukusic
mesh_terms: D000818:Animals; D003116:Color; D005241:Feathers / Q000033:anatomy & histology*; D046094:Galliformes / Q000033:anatomy & histology*; D008297:Male; D008962:Models, Theoretical; D055620:Optical Phenomena; D013057:Spectrum Analysis
keywords: multi-layered rigorous coupled-wave analysis; photonic crystal; spatial shift colour appearance; structural colour