A data-storage device based on silver ions embedded in glass could theoretically store 180 gigabytes per square centimetre — about 80 times the capacity of a Blu-ray disc.
Lionel Canioni at the University of Bordeaux in France and his team embedded a three-dimensional matrix of silver ions in light-sensitive glass. The ions fluoresce when hit with a laser. The researchers could control the silver's fluorescence at 16 discrete levels, coding information as varying levels of brightness rather than as the binary 'ones' and 'zeroes' that conventional magnetic storage devices use.
The authors managed to store and retrieve micrometre-sized pictures of three French Nobel prizewinners. Because glass resists wear from temperature and humidity, the authors say that it could be used for high-density information storage that lasts centuries.