2018/05/17 by Guo Liang Shang, Lukas Maiwald, Shang, Guoliang +13
Agricultural and Biological Sciences · Physics and Astronomy · #Fern and Epiphyte Biology #Ingenieurwissenschaften #Photonic Crystals and Applications #Plant and animal studies #applied optics #nanoparticles
paper · doi:10.15480/882.1665
openalex publication_date 2018/05/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Non-iridescent structural colors based on disordered arrangement of monodisperse spherical particles, also called photonic glass, show low color saturation due to gradual transition in the reflectivity spectrum. No significant improvement is usually expected from particles optimization, as Mie resonances are broad for small dielectric particles with moderate refractive index. Moreover, the short range order of a photonic glass alone is also insufficient to cause sharp spectral features. We show here, that the combination of a well-chosen particle geometry with the short range order of a photonic glass has strong synergetic effects. Using a first-order approximation and an Ewald sphere construction the reflectivity of such structures can be related to the Fourier transform of the permittivity distribution. The Fourier transform required for a highly saturated color can be achieved by tailoring the substructure of the motif. We show that this can be obtained by choosing core-shell particles with a non-monotonous refractive index distribution from the center of the particle through the shell and into the background material. The first-order theoretical predictions are confirmed by numerical simulations.