Detailed simulation of structural color generation inspired by the Morpho butterfly

The brilliancy and variety of structural colors found in nature has become a major scientific topic in recent years. Rapid-prototyping processes enable the fabrication of according structures, but the technical exploitation requires a profound understanding of structural features and material properties regarding the generation of reflected color. This paper presents an extensive simulation of the reflectance spectra of a simplified 2D Morpho butterfly wing model by utilizing the finite-difference time-domain method. The structural parameters are optimized for reflection in a given spectral range. A comparison to simpler models, such as a plane dielectric layer stack, provides an understanding of the origin of the reflection behavior. We find that the wavelength of the reflection maximum is mainly set by the lateral dimensions of the structures. Furthermore small variations of the vertical dimensions leave the spectral position of the reflectance wavelength unchanged, potentially reducing grating effects.