5D nanostructured quartz glass optical memory could provide ‘unlimited’ data storage for a million years
July 10, 2013
University of Southampton and Eindhoven University of Technology.scientists have developed a new technology that could store vast quantities of information — 360 TB on a disc, about 100 times more than current disk drives — for more than a million years .
‘Superman memory crystal’
Using a high speed femtosecond laser, data is written on self-assembled nanostructures created in fused quartz, and stored in five dimensions: size and orientation in addition to the three-dimensional position on the nanostructured material.
Each disc has three layers  of nanostructured dots, with dots separated by five microns (one millionth of a meter) . The self-assembled nanostructures change the way light travels through glass, modifying polarization of light that can then be read by combination of optical microscope and a polarizer, similar to that found in Polaroid sunglasses.
The glass-memory technology has been coined “Superman memory crystal,” as in the “memory crystals” in Superman movies.
The disc has thermal stability up to 1000°C (1832°F) and practically unlimited lifetime. As a test, a 300 kb digital copy of a text file was successfully recorded.
Ideal for massive long-term archival storage
The research is led by Jingyu Zhang from the University’s Optoelectronics Research Centre (ORC). “We are developing a very stable and safe form of portable memory using glass, which could be highly useful for organizations with big archives,” said Zhang.
“At the moment, companies have to back up their archives every five to ten years because hard-drive memory has a relatively short lifespan. Museums who want to preserve information or places like the national archives, where they have huge numbers of documents, would really benefit.”
Professor Peter Kazansky, the ORC’s group supervisor, adds: “It is thrilling to think that we have created the first document which will likely survive the human race. This technology can secure the last evidence of civilization: all we’ve learnt will not be forgotten.”
UPDATE July 10, 2013 from Prof. Zhang:
 For comparison: a Blu-ray disc can store 23.5 GB and lasts about 7 years.
 The final disc will have hundreds of layers; the three-layer structure was only to demonstrate this technique. A disc in this format that has the same thickness as a CD (1.2 mm) will have around 400 layers. It will look like a normal CD disc but made of glass.
 The targeted data density is one byte per spot in about a 5 cubic micron volume.
 A laser scanning device similar as the one used to read CD, DVD and Blu-ray is used to read the discs.