University of Glasgow plasmonics researchers have developed a technique that could prove a secure, stable alternative to dye-based printing for specialised purposes. Nanomaterial structural color filters produce two separate images that can be viewed with different lights in exactly the same place.

Research lead Dr. Alisdair Clark cited iridescence created across butterfly wing topography as a natural example of the properties he has been studying in nanoscale metallic structures.

The key breakthrough, which allows for dual-colored pixels, is in creating minute, cross-shaped piercings in aluminum film. The perpendicular line length varies according to the wavelengths of different colors, and thus each is observed via differently polarized light, shining through the indented film at a particular oscillation.

These nanopixels can be produced at 100,000 dots per inch (DPI), unlike those common in mass-media pigment printing at only 300 DPI. The superior resolution with the dual property, offering extraordinarily detailed images, creates exciting potential, particularly for anti-counterfeiting use.