It’s the little things…

With this size, you could fit over 200 million cards in a single postage stamp and seven quadrillion could fit into a letterbox, the equivalent of every person on Earth receiving 900,000 cards each.

It requires a powerful microscope to just see it,
let alone read the festive message inside. To make the card 10cm in height, it would have to be magnified by 5,000x; equivalent to blowing up a postage stamp to the size of a football field. 

The previous record holder measured 200x290 micrometres, with NPL’s
version being over 10x smaller. It’s made from platinum-coated silicon nitride and the front and message inside were carved by a focused ion beam. The tools used are helping to develop new techniques for understanding materials on a small scale, further the miniaturisation of
electronics and develop new battery material. 

Dr David Cox, Research Fellow at NPL, who created the card with his colleague Dr Ken Mingard, said: "While the card is a fun way to mark the festive season, it also showcases the progress being made in
materials research on this scale. We are using the tools that created the card to accurately measure the thickness of extremely small features in materials, helping to unlock new battery and semiconductor technologies. It's a genuinely exciting development that could help to make new technologies and techniques a reality."