An advanced version of the technology used to create DVDs and Blu-rays can store a lot more data, even if it takes a while
October 28, 2021
A new method of writing data to glass using lasers could store 500 terabytes on a single optical disc – but it takes so long to create that its applications may be limited.
The technique uses technology similar to existing optical media, but can store 10,000 times more data than Blu-ray discs. This is a laser that sends pulses every femtosecond – 1 quadrillionth of a second – to etch tiny holes in the glass.
Yuhao Lei of the University of Southampton, UK, and his colleagues call this method five-dimensional (5D) optical data storage because it uses two optical dimensions, based on the polarization and intensity of light, as well as the usual three spatial dimensions, to record data.
In tests, the researchers managed to write 6 gigabytes of data onto a 1-inch square of glass. They could read back the data with an accuracy of between 96.3 and 99.5 percent, which could be improved to 100 percent with an error-correction algorithm, Lei says.
“The main challenge for us is write speed,” he says, as they could only write 225 kilobytes per second, which means the 6 gigabytes took about 6 hours. “We are not currently doing parallel writing [where multiple laser beams write onto the material]. We are working to improve this.
“This data storage is very durable and can withstand high temperatures, meaning it can live almost forever,” says Peter Kazansky, a member of the University of Southampton team.
With small tweaks, the write speed could become four times faster, Kazansky says – although he’s not yet sure if this could significantly increase the risk of errors. The intention is to provide a storage method for the national archives, Lei said.
“It’s great to see the seemingly dramatic improvements in write speeds and overall performance of this storage technology in a lab environment in just a few years,” says Ben Fino-Radin of Small Data Industries, a New York-based archiving company, indicating a 75-fold improvement over an earlier version of the technique that could only write at 3 kilobytes per second in 2017. “What remains unclear is what practical role 5D glass storage could hypothetically play in the future.”
Journal reference: Optical, DOI: 10.1364/OPTICA.433765
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