2D photonic-crystal structures of Papilio blumei butterfly were constructed and the corresponding reflectance spectra were simulated by finite-difference time-domain (FDTD) method. The structural color of butterfly depends on the thickness of film and the size of air hole. Hence, we can obtain any color by manipulating the parameters of FDTD simulation model.
The iridescence green band and cyan tail of the wing on Papilio blumei butterfly were investigated. The bi-color phenomenon on the scales of butterfly wings was found and analyzed. The spectral change with thickness of chitin-air layers, width of air hole, total layer numbers and incident angle of light were simulated by FDTD method. 2D photonic-crystal model was applied to explain the change of reflectance spectra and color with angle. The replica of structural color and nanostructured thin films for Papilio blumei butterflies was fabricated successfully by three main techniques, PS spheres bedding, electron-beam gun evaporation and ICP etching.
Although the physics of structural color has been investigated, it remains a challenge to create artificial replicas of the natural photonic crystal structure. The concave multilayer replica of Papilio blumei butterflies is successfully fabricated by the following three main steps: self assembly of polystyrene spheres, deposition using an electron-beam gun, and inductively coupled plasma etching. The green iridescence of the wings of P. blumei is successfully reproduced.
Butterfly's wing has paid great attention due to its unique properties, such as attractive iridescence, super-hydrophobic
characteristics, and quick heat dissipation ability. These characteristics are closely related to its structure. The multilayer
thin-film structures that make up a butterfly's wing produce a bright iridescence from reflected daylight. In this study, we
will introduce the optical effect of viewing angle, structural characterizations and color-producing mechanism. Since the
reflectance patterns are extended in angle, we have to use a spectrophotometer equipped with an integrating sphere.
According to the result, the peak reflectrance decreasing, blue-shifts and the difference between spectra of p-polarization
and the s-polarization was enlarged when the incident angle increasing. In addition, the directional and strongly angle-dependent
reflection of the ventral wings suggests the question whether or not the wing reflections may play a role in
visual signaling by the butterflies during flight. Furthermore, we determined the shape and surface texture of the scales
by scanning electron microscope (SEM). From SEM images, the scales cover the wing membrane and appear to overlap
like roof tiles. These nanometer structures of the cover scales will decide the attractive iridescence of the wing.