In the city of Aquileia in Italy, a group of researchers has found among the remains of a site of the Roman Empire an unthinkable discovery. These are fragments of photonic crystals, 21st century materials commonly used in cutting-edge military and scientific applications.
In the first moment, They thought they were glass from vases and bottles of the time Roman buried in the mud, but they turned out to be cutting-edge nanomaterials. “It’s really remarkable that you have glass that’s been in mud for two millennia and you end up with something that is a textbook example of a nanophotonic component,” said Fiorenzo Omenetto, an engineering professor at Tufts University who conducted the study. discovery together with Giulia Guidetti.
The discovery occurred by chance, as stated in the magazine Natureand occurred during a visit to the Italian Institute of Technology, when Omenetto and Guidetti were dazzled by a “beautiful shiny piece of glass on a shelf.”
Both researchers have discovered that the molecular structure of These glass fragments have been modified for thousands of years underground thanks to the environmental factors and the minerals that surrounded them, transforming them into these nanocrystals.
These Photonic crystals have atomic structures arranged in a certain way that allow you to create unique optical effects due to the way they filter and reflect light. The discoverers found that, although much of the fragment retained its original color, “on its surface there was a patina that reflected light like a golden mirror.” This was due to structures called Bragg stacks, alternating layers of high and low density silica, which reflect different wavelengths, giving rise to that golden color.
These crystals found in nature have important technological potential, as researchers recall, they can be used in the creation of lasers, filters and mirrors. Its properties also make it susceptible to creating anti-reflective surfaces typical of military invisibility used in vehicles and airplanes.
“If we could significantly speed up the process in the laboratory, we could find a way to grow optical materials instead of manufacturing them,” said Omenetto.