Cranfield celebrates Coronation of King Charles III with microscopic engraving

According to the team, the engraving is so small that it can only be seen using a powerful microscope.

Gold microscopic letters – each a fraction of the width of a human hair – form part of a commemorative piece to mark the King’s coronation. It depicts the official cyphers of King Charles III and Queen Camilla, and lettering below reads ‘Westminster Abbey 6^th May 2023’.

The framed exhibit – created using a focused ion beam scanning electron microscope (FIB-SEM) - is being displayed alongside high-magnification images to commemorate the occasion. The exhibit was created in the electron microscopy suite at Cranfield, using ion microscopes that are routinely used to examine evidence of micro defects within aerospace technology, such as engine components.

An additional feature is that the letters were made using recycled gold from the coating equipment used to prepare samples for imaging in the microscope. The FIB-SEM works best when samples are very conductive, so many require a thin layer of gold on them to prevent charging of the sample surface, researchers explained.

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The microscope works by bombarding a sample with a beam of ions to selectively remove material, and then creates highly-detailed images of it. The team said that the project took around two hours to manufacture.

Dr Diane Johnson, senior technical officer – materials characterisation (SEM) at Cranfield University, who led the team, said: “This project not only showcases our expertise in nanotechnology and microscopy, but also demonstrates a way in which we can use our equipment in a creative and unusual way.

“To create this microscopic message, we used a very high purity 99.99 per cent piece of gold foil measuring 15mm x 10mm x 0.2mm thick. With these microscopic symbols, we have marked the special and historic occasion of the Coronation of King Charles III.”