Library in a glass chip: laser-writing trick can store vast amounts of data

An team of UK researchers has figured out a laser-writing technique that can store vast amounts of data in glass.

So-called five-dimensional (5D) data storage uses molecule-sized nanostructures created in silica glass to store information, and is 10,000 times denser in storage than a Blu-Ray disc.

“Individuals and organisations are generating ever-larger datasets, creating the desperate need for more efficient forms of data storage with a high capacity, low energy consumption and long lifetime,” says Dr Yuhao Lei, a researcher at the University of Southampton, UK, and lead author on a paper in Optica describing the technique.

The technique can write at speeds of roughly a million voxels per second, equivalent to recording 230 kilobytes of data per second. This isn’t particularly fast compared to conventional data storage – a test chip created by the researchers took months to write and then read five gigabytes. But the silica is more stable, and much denser, than other methods, making it useful for information that has to last.

“While cloud-based systems are designed more for temporary data, we believe that 5D data storage in glass could be useful for longer-term data storage for national archives, museums, libraries or private organisations,” says Lei.

Read more: How to preserve data to last 13.8 billion years

Five-dimensional optical storage is not a new concept, but it’s previously not been fast or dense enough to be a feasible storage method.

Lei and colleagues have improved the technique by using a laser that sends out pulses of light at ultrashort intervals – every femtosecond (10^-15 seconds) or so. This laser creates tiny pits in glass, called nanostructures, ranging between 50 and 500 nanometres in size (or less than half the width of a bacterium). By tuning the way the laser pulsed at the glass, using a phenomenon called near-field enhancement, the researchers were able to create nanostructures more effectively without damaging the chip.

“This new approach improves the data writing speed to a practical level, so we can write tens of gigabytes of data in a reasonable time,” says Lei.

“The highly localised, precision nanostructures enable a higher data capacity because more voxels can be written in a unit volume. In addition, using pulsed light reduces the energy needed for writing.”

The researchers are now determining ways to increase the speed of the writing, and planning to bring the technology outside the lab.