The world’s smallest QR code is ‘smaller than most bacteria’

For those of us not paying attention, in recent years scientists around the world have been competing to try to create the smallest QR code that can be reliably read. Now Austria-based researchers have set the bar very high with a QR code so small you need an electron microscope to see it.

Materials scientists at the public research university TU Wien in Vienna have shrunk the specialized barcode to an area of ​​1.98 square micrometers, which is smaller than many bacteria and invisible to optical microscopes. It’s official earned the team a place in the Guinness World Records.

“Structures on the micrometer scale are nothing unusual these days – it is even possible to fabricate patterns made of individual atoms,” says Professor Paul Mayrhofer from the Institute of Materials Science and Technology at TU Wien. “But that alone does not result in stable, readable code.”

Indeed, the previous record for the smallest QR code was prepared by a Germany-based team from the University of Münsterwhere a pattern was placed in an area of ​​just 5.38 square micrometers – many times smaller than a human red blood cell. So an advancement in this niche wasn’t just about shaving off a few micrometers this way and that, but also about ensuring that the QR code was usable in that small coding area for a long period of time.

The team has collaborated with German startup Cerabytewhich specializes in long-term data storage technology, and chose to use a thin ceramic film as the medium. The idea here was that this material would remain stable under all conditions for extended periods of time, so that the code etched on it would be readable repeatedly.

The researchers used focused ion beams to mill the QR code onto the ceramic film, with the individual pixels each measuring just 49 nanometers. At this size, those pixels are about 10 times smaller than the wavelength of visible light – meaning you would never be able to see this detailed code with visible light. Instead, it can only be viewed using an electron microscope.

This makes the QR code of the TU Wien team almost three times smaller than that of the previous record setter. But more importantly, it promotes the development of sustainable, high-density data storage technology for the world’s growing information archiving needs. The researchers note that an A4-sized ceramic film can hold more than 2 TB of data.

Of course, much more work needs to be done in developing it. The scientists want to advance their research by exploring data structures other than QR codes for writing data, as well as other materials for reliable, energy-efficient long-term storage. They also plan to explore how it can be made available outside the laboratory setting.

The ceramic technology could conflict with alternative data storage technologies currently being researched, including the use of DNA suspended in amber, a special magnetic molecule that allows small drives to store large amounts of data, an entirely new form of magnetism for next-generation hard drives, and Microsoft’s approach to etching data into glass using lasers.

Source: TU Vienna