Engineers based at the University of Glasgow have created the world's smallest Christmas card using nanotechnology, and it's so small that they could fit 8,276 of them on a single first class postage stamp.

The Christmas tree image and message is invisible to the naked eye and was etched on a piece of glass by Professor David Cumming and Dr Qin Chen from the University’s School of Engineering, in order to show off their nanotechnology expertise.

They also created the tiny greeting to help explain the potential of nanotechnology science:

"Our nanotechnology is among the best in the world but sometimes explaining to the public what the technology is capable of can be a bit tricky".

"We decided that producing this Christmas card was a simple way to show just how accurate our technology is. The process to manufacture the card only took 30 minutes. It was very straightforward to produce as the process is highly repeatable - the design of the card took far longer than the production of the card itself".

"The card is 200 micro-metres wide by 290 micro-metres tall. To put that into some sort of perspective, a micro-metre is a millionth of a metre; the width of a human hair is about 100 micro-metres. You could fit over half a million of them onto a standard A5 Christmas card - but signing them would prove to be a bit of a challenge".

In addition to the etching work, the colours were produced by plasmon resonance in a patterned aluminium film made in the University’s James Watt Nanofabrication Centre.

And while the entire project was performed for a bit of fun, similar processes are currently being tested by the electronics industry for bio-technology sensing, optical filtering and light control components, and could be seen in digital gadgetry, such as cameras and televisions, in the future.