Figure 6.

Mimicking the hierarchical surface micro-/nanostructures of the Morpho butterfly and coloration tuning by the variation of the phontonic structure’s size. The resulting coloration based on 2PP fabricated photonic structures are shown in (A)–(C). The associated SEM images of the microstructures are presented in (D)–(F). The oblique views of the microstructures demonstrates the hierarchical design containing air cavities and polymer lamellas. The total height of the microstructure was measured with white-light interferometry and is L = 1 μm. Since the number of periods is five, the total dimension of one air cavity and one artificial lamella for the resulting blue coloration (C) is 200 nm (d ₁ ~ 50 nm, d ₂ ~ 150 nm), which fits the air and cuticula dimensions inside the Christmas tree shape of a Morpho ridge. Whereas, the photonic microstrucutres of the purple coloration have decreased polymer lamellas d ₁ ~ 40 nm and increased air cavities d ₂ ~ 160 nm. The microstructures of the green coloration have the same amount regarding the dimensions of the polymer lamellas and air cavities (~100 nm).