Morpho butterfly's metallic blue luster, which is produced from the butterfly's scale, has a mysterious feature. Since the scale does not contain a blue pigment, the origin of the coloration is attributed to a microscopic structure that can also explain its high reflectivity. However, it appears blue from wide angular range, which contradicts obviously the grating or multilayer. The mystery of the lack of multi-coloration has recently been explained with a peculiar nano-structure, and experimentally proven by fabricating the optical film by controlling the parameters in nanoscale. The reproduced Morpho-blue was found to be important from viewpoint of a wide variety of applications. However, optical properties of the fabricated film were found to contain still some differences with that of the Morpho-butterfly, although the basic characteristics of the Morpho-blue itself was reproduced. In order to make the artificial Morpho-blue closer to the natural one than the prototype, we attempted to optimize the artificial film structure by controlling fabrication parameters. In this process, optical simulations and micro-structural observations were taken in account. By comparing a series of films fabricated with different nano-patterns, optimized parameters were semi-empirically obtained. Also the relationship between the structural parameters and the optical properties was analyzed. The reflective characteristics of the optimized film were found to reproduce the optical properties more closely to the natural Morpho-blue than the prototypes.

Date Published: 15 October 2007
PDF: 8 pages
Proc. SPIE 6767, Photonic Crystals and Photonic Crystal Fibers for Sensing Applications III, 676706 (15 October 2007); doi: 10.1117/12.733954

Published in SPIE Proceedings Vol. 6767:
Photonic Crystals and Photonic Crystal Fibers for Sensing Applications III
Henry H. Du; Hiroshi Fudouzi, Editor(s)