With an advanced version of the technology behind DVDs and Blu-rays, much more data can be stored than before – although it will take a while.
A new method of writing data on glass with lasers makes it possible to store 500 terabytes on a single optical disc. It just takes so long to write that the applications are likely to be limited.
The method uses the same technology as existing optical storage media, but can store 10,000 times more data than Blu-ray discs. This involves a laser that emits pulses every femtosecond – one quadrillionth of a second – that etch tiny holes in the glass.
Five dimensions
Yuhao Lei, a PhD student in optoelectronics at the University of Southampton in the United Kingdom, and his colleagues call the new method “five-dimensional optical data storage.” The method uses two optical dimensions, based on the polarization and intensity of light, in addition to the usual three spatial dimensions.
In an experiment, the researchers managed to write 6 gigabytes on a glass square of about 6.5 square centimeters. They were able to read back the data with an accuracy of between 96.3 and 99.5 percent, which could have been 100 percent had they used an error-correction algorithm, Lei says.
Save faster
“Our biggest challenge was storage speed,” he says, as the researchers could only store 225 kilobytes per second. That means 6 gigabytes would take about 6 hours. ‘At the moment we do not store in parallel (where several lasers write on the material, ed.). We’re trying to improve that.’
“This data storage is very durable and can withstand high temperatures, which means it has almost eternal life,” said team member Peter Kazansky, professor of optoelectronics at the University of Southampton.
With minor adjustments, the storage speed can be four times faster, says Kazansky – although he believes that could significantly increase the chance of errors. The ultimate goal is to develop a storage method for national archives, says Lei.
“It’s great to see the major improvements in storage speed and overall performance of this storage technology under lab conditions that have been made in just a few years,” said Ben Fino-Radin, founder of New York archiving company Small Data Industries. He is referring to an improvement of the technology by a factor of 75 compared to 2017. At that time, only three kilobytes per second could be stored. ‘It remains unclear what practical role 5D glass storage could play in the future.’