There Lycurgus’ cup It is a Roman artefact of the 4th century AD which represents one of the first testimonies of the use of nanotechnologywhile involuntary. This fascinating example of glass art not only impresses with its beauty, but also reveals advanced technical knowledge And scientific by its creators; in fact this diatreta cup (now preserved in the British Museum) changes colour depending on the direction of light (reflected or transmitted), a phenomenon that is due to dispersion of metal nanoparticles in glass.
The characteristics of the Lycurgus Cup
There Lycurgus’ cup takes its name from the mythological character depicted on its surface: Lycurgus, king of Thrace, depicted in a scene of divine punishment. The cup was discovered in 19th century and has since then attracted the interest of art historians, archaeologists and scientists. It is currently preserved at the British Museum, Londonwhere it continues to be studied to reveal the secrets of its manufacturing.
The most striking feature of the Lycurgus Cup is its changing color: appears green when illuminated from the front and red when internally illuminated. This effect is caused by the presence of gold, silver and manganese nanoparticlesand dispersed in the glass. Their size is about 70nm and their distribution are such as to influence the way in which light is absorbed and diffused, thus creating the phenomenon of dichroism.
The phenomenon of the dichroism of the Lycurgus cup can be explained through the theory of plasmonics, a branch of physics that studies the interaction between light and metallic nanoparticles. When the light hits nanoparticlesthe electrons on their surface oscillate in response to the electromagnetic field of light. This movement of electrons, known as plasmon resonancedetermines the absorption and scattering of light, causing the observed color change.
How the Lycurgus Cup was made
The Roman craftsmen who created the Lycurgus Cup probably they were not aware of the optical properties of nanoparticles, but were masters at manipulating glass and metals to achieve extraordinary visual effects. The manufacturing process involved theaddition of tiny quantities of metal powders in the molten glass. These powders, uniformly distributed during glass blowing, gave rise to the dispersion of nanoparticles.
The Lycurgus Cup is not the only example of the use of nanotechnology in antiquity. During the Middle Ages, European craftsmen used similar techniques to create stained glass windows of Gothic cathedrals. Again, the addition of metal nanoparticles to the glass gave the windows their vibrant, iridescent colors. Depending on the size, material, and shape of these metallic nanoparticles, the glass appeared a different color. For example, by dispersing spherical gold particles with an average size of about 50nm you get a green-yellow glass, If instead these nanoparticles have double the size, we obtain a coral glass. If the nanoparticles are the same size but made of silver, you get a bright red glass. Some stained glass windows produced with this technique are found in Florence at Santa Maria Novella and in Paris at Notre Dame. These practices show that, although the term “nanotechnology” is modern, the manipulation of matter at the nanometric level has ancient roots.
Modern Implications and Inspirations
The Lycurgus Cup continues to inspire modern research. The phenomenon of plasmon resonance has been of interest to the scientific community for the past 20 years because it allows us to explore previously unknown properties of materials. At the moment, the use of plasmonics remains confined to advanced research applications such as in sensors for monitoring biological molecules and the confinement of light. In particular, light confinement is of great interest as it opens the way to numerous innovative applications in various fields, from medicine to electronics.
