With advanced versions of the technology behind DVDs and Blu-rays, more data can be stored than ever before – although it will take some time.

A new method for writing data on glass with a laser makes it possible to store 500 terabytes on a single optical disc. It just takes a long time to write so applications tend to be limited.

This 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 emitting a pulse every femtosecond – one millionth of a second – that scratches a tiny hole in the glass.

Five dimensions

Yuhao Lei, a PhD student in optoelectronics at the University of Southampton in the UK, and his colleagues call the new method “five-dimensional optical data storage.” This method uses two optical dimensions, based on the polarization and intensity of light, in addition to the usual three spatial dimensions.

In one experiment, the researchers managed to write 6 gigabytes on a square glass 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 if they had used an error-correcting algorithm, Lei said.

Save faster

“Our biggest challenge is storage speed,” he said, as the researchers could only store 225 kilobytes per second. That means 6 gigabytes will take about 6 hours. ‘We don’t currently store in parallel (where multiple lasers write on the material, ed.). We’re trying to improve on that.’

“This data store is extremely durable and can withstand high temperatures, which means it has an almost eternal life,” said team member Peter Kazansky, professor of optoelectronics at the University of Southampton.

With a little tweaking, storage speeds could be up to four times faster, says Kazansky — though he believes it could significantly increase the chance of error. The main goal is to develop a method of keeping the national archives, Lei said.

“It’s great to see the huge improvements in storage speed and overall performance of this storage technology under lab conditions that have been created in just a few years,” said Ben Fino-Radin, founder of New York filing firm Small Data Industries. He referred to the technology improving by a factor of 75 over 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.’