The brightest colours in nature arise from the interaction of light with surfaces that exhibit periodic structure on the micro and nanoscales. In the wings of butterflies, for example, a combination of multilayer interference, optical gratings, photonic crystals and other optical structures gives rise to complex colour mixing, but it remains a challenge to create artificial replicas of natural photonic structures. Now Ulrich Steiner, Jeremy Baumberg and co-workers have used a combination of growth processes — including self-assembly, sputtering and atomic-layer deposition — to fabricate photonic structures that mimic the colour-mixing effect found on the wings of the Papilio blumei butterfly, and to make new structures that display enhanced optical properties. The background image is an optical micrograph of a scale taken from a butterfly wing.
Cover design by Karen Moore