POS4-0663
Angle-Dependent Photonic Microdome Arrays for Multimodal Color Graphics
Topic
S4. Colloids, Interfaces, and Molecular Assemblies for Functional Soft Materials
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Jun-Gu Kang (KAIST)
Co-Author(s)
Abstract
Structural coloration provides a pigment-free strategy for creating optical materials whose appearance is controlled by nanoscale and microscale architecture. In this study, we present a programmable hybrid photonic platform that integrates shear-aligned colloidal photonic crystals with hemispherical microdome arrays to generate dynamically switchable visual responses. The hierarchical structure combines angle-dependent Bragg reflection from periodically ordered silica particles with curvature-mediated total internal reflection interference within the microdomes, enabling four reversible optical states controlled by viewing angle and microdome orientation. The microdome-on-film architecture is fabricated by confined molding of photocurable silica suspensions using dimple-patterned templates, where shear flow promotes ordered colloidal assembly before photopolymerization. The resulting optical output, including hue, brightness, and spatial contrast, can be systematically tuned by adjusting the silica particle diameter and volume fraction, as well as the radius and areal density of the microdomes. Using these design parameters, we demonstrate angle-responsive color graphics that remain concealed under normal observation from the film side but are revealed under tilted viewing or from the microdome side through the transition between dominant photonic stopband reflection and curvature-induced interference. This scalable and lithography-compatible approach offers a robust route to spatially programmable structural color materials with potential applications in smart labels, anti-counterfeiting technologies, optical encryption, and tunable photonic surfaces.
