Let Colour Take the Strain

Imagine a material that doesn’t contain colour in the usual way—no dyes, no pigments—yet it is colourful. It can sweep smoothly from red to blue simply by being stretched and then snap back again when released.

That’s the essence of a new ‘nanoscale chameleon’ demonstrated by researchers at the University of Amsterdam1: a surface whose colour is not a chemical property, but a mechanical and optical one.

At the heart of the work is a metasurface: a carefully patterned layer where features are smaller than the wavelength of visible light. At this scale, light doesn’t just bounce off as it would from a mirror. Instead, it interacts with an array of tiny elements—like nano-sized antennas—that can trap, scatter, and re-emit light in very specific ways. The result is structural colour, a phenomenon also seen in nature (look at a peacock feather or butterfly wings), where colour comes from micro- and nanostructure rather than pigment.