Printing Structural Colour Like a Newspaper

Structural colour has been extensively covered in Holography & Optical Technology News™, and in other technical publications concerned with nano-optics and optical security. The principle is well established. Namely, colour is generated not by dyes or pigments, but by structures whose dimensions are comparable with, or smaller than, visible wavelengths of light.

The latest work described in this article is of interest not only because it demonstrates a new approach to generating structural colour but also because it addresses the difficult transition from finely controlled laboratory structures to continuous, economical production.

Optical effects at two scales

Reported in the journal Nature as ‘Printable meta-assemblies enable synergetic colouration’, the research was led by the Institute of Chemistry of the Chinese Academy of Sciences with collaborators in Singapore ¹. The team created a layered optical metamaterial comprising periodically arranged polystyrene nanoparticles embedded in a flexible polydimethylsiloxane (PDMS) matrix. The nanoparticle lattice is itself formed into a micro-scale concave optical interface. The result is not a single photonic structure, but an optical system operating simultaneously at nano- and micro-scales.