Synthetic dyes have found widespread application in almost all walks of modern life, including medicine, electronics, food and textiles. Despite their immense utility, they tend to have limited brightness, degrade over time and can be harmful to the environment. Accordingly, attention has turned to production of color by other means. Of special interest is structural color. Structural coloration results from the interaction of visible light with periodic microstructures (or nanostructures) on surfaces, which causes diffraction, interference, and scattering. Color produced in such a manner is vibrant, tunable and stable, and is often found in living organisms, such as insects, birds and even mammals.
Despite the unique features of structural color, it is normally difficult to artificially generate on a large scale. To address this issue, Xiaobao Cao and collaborators have taken inspiration from the wings of the Brilliant Nymph butterfly (Cyanandra Opis’) and have fabricated bigrating nanostructures using two-photon stereolithography. By varying the height and period of the grating features, the authors can tune color, hue and purity in a controllable fashion across the entire visible portion of the electromagnetic spectrum.
The approach is robust, scalable and can produce complex color palettes with ease. In the future, the authors intend to use the results of the study to better understand the biological origins of structural color, and additionally hope to generate unique optical properties through the introduction of disorder into their gratings
Written by Andres Rocha Tapia
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