Brilliant Structural Color in Animals and its Application

Abstract

There are many animals that show metal-like glittering colors like a jewel beetle. These colors are produced by microstrutures comparable with the wavelength of light, and thus, they are called structural colors. Various color-causing microstructures have been found such as multilayer and photonic crystals. The periodic microstructure causes the constructive optical interference at the wavelength of visible light, resulting a higher reflectance at specifice wavelenghs of light. However, rather than simple optical interference, animals have been found to utilize various factors to make the color brilliant and saturated. In this article, we describe the coloraition mechanisms for several types of microstructures with some biological examples. In addition, we mention the coloration mechanisms of a photonic ball, which is an artificially produced spherical aggregation of collidal particles.