Colour images with an effective resolution of up to 100,000 dots per inch — the maximum possible owing to the properties of visible light — could now be a reality, thanks to researchers in Singapore.

Joel Yang at the Institute of Materials Research and Engineering in Singapore and his colleagues began with a silicon wafer and created tiny posts tens of nanometres in diameter on the surface. The posts were capped with silver disks. Depending on their size and spacing, groups of posts preferentially reflected a single colour back towards the viewer. Using their system, the researchers created colour images (pictured), which could be resolved at the diffraction limit of optical microscopes.

The posts could be used in security images and in optical filters or data storage, the team suggests.

Nature Nanotechnol. http://dx.doi.org/10.1038/nnano.2012.128 (2012)