Light Angle

A burst of colour is a universal form of communication. We react to it – seeing danger, or maybe calm – it’s also a quick way to monitor changes during medical tests. Scientists and engineers are on the lookout for new ways to split, or refract, white light into its rainbow spectrum on demand. Here dishes of oil droplets display iridescence – illuminated with white light, they appear in different colours from different angles, creating a rainbow shimmer. The secret lies in obstructing the path of the light, a process known as structural colour – in this case two types of particles in the oil meet creating a hemisphere shape which refracts the light into coloured waves. It’s possible to manipulate these patterns, raising the possibility of using similar techniques to create iridescent paints, or perhaps new colorimetric sensors, worn of the body to keep tabs on bodily processes.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Image from the Zarzar Lab, Penn State University
• The Pennsylvania State University, University Park, PA, USA
• Image copyright held by the original authors
• Research published in Nature, February 2019