Ewald sphere construction for structural colors

Abstract

Disordered structures producing a non-iridescent color impression have been shown to feature a spherically shaped Fourier transform of their refractive-index distribution. We determine the direction and efficiency of scattering from thin films made from such structures with the help of the Ewald sphere construction which follows from first-order scattering approximation. This way we present a simple geometrical argument why these structures are well suited for creating short wavelength colors like blue but are hindered from producing long wavelength colors like red. We also numerically synthesize a model structure dedicated to produce a sharp spherical shell in reciprocal space. The reflectivity of this structure as predicted by the first-order approximation is compared to direct electromagnetic simulations. The results indicate the Ewald sphere construction to constitute a simple geometrical tool that can be used to describe and to explain important spectral and directional features of the reflectivity. It is shown that total internal reflection in the film in combination with directed scattering can be used to obtain long wavelength structural colors.

References in corpus (4)

• Biomimetic isotropic nanostructures for structural coloration
• Absence of Red Structural Color in Photonic Glasses, Bird Feathers and Certain Beetles
• Double scattering of light from biophotonic nanostructures with short-range order
• A quantitative first-order approach for the scattering of light by structured thin films

Cited by in corpus (4)

• Angular Independent Photonic Pigments via the Controlled Micellization of Amphiphilic Bottlebrush Block Copolymers
• Designing angle-independent structural colors using Monte Carlo simulations of multiple scattering
• Effects of multiple scattering on angle-independent structural color in disordered colloidal materials
• Density of photonic states in aperiodic structures