Details

Autor(en) / Beteiligte

• Schertel, Lukas
• Siedentop, Lukas
• Meijer, Janne‐Mieke
• Keim, Peter
• Aegerter, Christof M.
• Aubry, Geoffroy J.
• Maret, Georg

Titel

The Structural Colors of Photonic Glasses

Ist Teil von

• Advanced optical materials, 2019-08, Vol.7 (15), p.n/a

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2019

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• The color of materials usually originates from a combination of wavelength‐dependent absorption and scattering. Controlling the color without the use of absorbing dyes is of practical interest, not only because of undesired bleaching properties of dyes but also regarding minimization of environmental and health issues. Color control without dyes can be achieved by tuning the material's scattering properties in controlling size and spatial arrangement of scatterers. Herein, calibrated photonic glasses (PGs), which are isotropic materials made by random aggregation of nonabsorbing, monodisperse colloidal polystyrene spheres, are used to generate a wide spectral range of purely structural, angular‐independent colors. Experimental reflectance spectra for different sized spheres compare well with a recent theoretical model, which establishes the latter as a tool for color mapping in PGs. It allows to determine the range of visible colors accessible in PGs as function of size, packing fraction, and refractive index of scatterers. It also predicts color saturation on top of the white reflectance as function of the sample's optical thickness. Blue, green, and red are obtained even with low index, while saturated green, cyan, yellow, and magenta can be reached in higher index PGs over several orders of magnitude of sample thickness. The range of achievable isotropic structural colors in photonic glasses is controlled by tuning size, spatial arrangement, and refractive index of spherical colloidal scatterers. Experimental reflectance spectra compare well with a recent theoretical model establishing the latter as a tool for color mapping. It further predicts color saturation as function of the sample's optical thickness.