Bank notes, fraud and butterfly wings

bank notes and credit cards could be made harder to counterfeit after scientists copied the iridescence of a butterfly's wings.

Iridescent colour is produced by way light bounces off a structure rather than through the use of pigments and has long fascinated physicists and biologists.

Using Indonesian Peacock butterflies, Papilio blumei, as a template, researchers have used nanofabrication techniques to build a structure identical to that incorporated within butterfly scales. They made such accurate copies that the manufactured versions reflect colours in exactly the same shades as the real scales and incorporating the structures into banknotes will make them far more difficult to forge.

The results of the experiments are published in Nature Nanotechnology.