Tiny Metallic Pixels Could Make Pictures That Never Fade

By Jamie Condliffe on at

With time, paint and pictures lose their intensity. But tiny metallic pixels could be used to create vivid images and paintworks that never lose their lustre — and the resulting pictures are becoming more detailed than ever.

These aluminium pixels — known as plasmonic pixels — aren’t entirely new. They’ve been used in the past to create small and simple images just a few microns wide, as well as block-colour screens that can be tuned to change between red, green and blue shades. Now, though, a team from the University of Melbourne has used the pixels to create detailed colour images.

The plasmonic pixels make use of the free electrons that float around within metals. Make a small aluminium pixel in the right size and shape, and those electrons vibrate at a particular frequency, which in turn gives off a specific colour of light. In fact, the size dictates the colour and the gaps between neighbouring pixels the saturation.

The Melbourne team has now developed a new design and manufacture process that allows it to create 2,000 different types of the pixel, which corresponds to 2,000 different colours and shades. That provides a far richer pallet from which to create images than researchers have had access to in the past.

An example of what can be achieved is at the top of the page: the image on the left is an actual photograph, while in the middle and on the right are representations made using the plasmonic pixels. The plasmonic image measures just over a centimetre across; that's large compared to previous microscopic images created using the same technique. Currently it looks washed out compared to the real picture, but with more pixels to choose from, it will only ever look better.

The team reckons that the technique could be used to print never-fading, high-resolution images, which may be of use for security tags, medical packaging — or simply images that you never want to say goodbye to. [Nano Letters via PhysOrg]