(Image: Dik Wiersma/SPL)
Hard drives can be wiped. DVDs degrade. So let’s do like Superman and record our most precious memories in shards of data-hungry glass
In the Superman comics, the eponymous hero occasionally flies to a crystal fortress where he can access memories of his long-obliterated homeland, stored in shards of crystal. Wouldn’t it be nice if we could find somewhere to store our memories indefinitely, too? Of course, we already have lots of options for storing information. But hard-disc drives can easily be wiped, while flash memory can be damaged by high temperatures and deteriorates after a several thousand write cycles. Even DVDs oxidise after a few decades – if they don’t get scratched first.
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Safe long-term data storage is a concern for us all today. Future human or even alien civilisations might also appreciate us keeping orderly records. It turns out, to fulfil that futuristic vision, we could do worse than emulate Superman’s shards.
In 1996, physicists at Harvard University showed that it ought to into a durable transparent material such as glass. Glass is resistant to heat, chemicals and mechanical stress – and can even be made bulletproof. According to the Harvard scheme, writing a bit of information to it would be as simple as focusing an intense laser to create a tiny defect with a different refractive index to the surrounding glass. You could read the information by exposing the material to light, and examining the pattern of spots bouncing off the defects.
The vision has taken a while to realise largely because it requires meticulously focused lasers, which are a fairly new technology. But the Japanese company Hitachi is now planning to bring a memory material made of fused quartz, a type of glass, to the market next year.
Physicist and his team at the University of Southampton, UK, want to go a step further. They think it is possible to record data into fused quartz in five “dimensions”, using not just the three spatial dimensions of the crystal to write different bits of information but also the effects of varying the intensity and polarisation of the writing laser. The result would be a storage density as much as eight times greater than Hitachi’s method, and enough to cram terabytes into a piece of glass the size of a thumbnail (). Kazansky’s group has calculated that its medium would be stable up to 1000 °C, could survive a nuclear holocaust and would persist for upwards of 10 billion years. “That’s comparable to the age of the universe,” says Kazansky.
His group is now trying to improve the rate at which data can be written to the glass from the current rate of kilobytes per second to megabytes. That would be fast enough to allow a video recording to be written to it in real-time, and preserved for any curious peoples of the future. Surely enough to satisfy even Superman.
Read more: “Wonder stuff: Seven new materials to change the world“
This article appeared in print under the headline “Future stuff: Memory glass”
