posted on 2021-10-18, 19:45authored byHemant
Kumar Raut, Hao Wang, Qifeng Ruan, Hongtao Wang, Javier G. Fernandez, Joel K. W. Yang
Structural
coloration is a recurring solution in biological systems
to control visible light. In nature, basic structural coloration results
from light interacting with a repetitive nanopattern, but more complex
interactions and striking results are achieved by organisms incorporating
additional hierarchical structures. Artificial reproduction of single-level
structural color has been achieved using repetitive nanostructures,
with flat sheets of inverse opals being very popular because of their
simple and reliable fabrication process. Here, we control photonic
structures at several length scales using a combination of direct
laser writing and nanosphere assembly, producing freeform hierarchical
constructions of inverse opals with high-intensity structural coloration.
We report the first 3D prints of stacked, overhanging and slanted
microstructures of inverse opals. Among other characteristics, these
hierarchical photonic structures exhibit geometrically tunable colors,
focal-plane-dependent patterns, and arbitrary alignment of microstructure
facet with self-assembled lattice. Based on those results, novel concepts
of multilevel information encoding systems are presented.