Our knowledge of the past comes from stone tablets and old parchment. But thousands of years from now, our descendants may learn of our lives from a thin slice of glass carrying an impressive load of data—all thanks to physics that sounds borderline magical.
Today, Microsoft’s Project Silica unveiled the latest technological advances in what is essentially laser-modified glass storage for sensitive data. Described in a Nature paper, the system, called Silica, works somewhat like a multidimensional CD. But the revolutionary—perhaps strange—aspect of the technique is that it harnesses the properties of light to encode gigabytes of data within a tiny square of borosilica glass roughly 0.08 inches (2 millimeters) thick.
What’s more, the material could theoretically last 10,000 years, potentially making it the ultimate storage device.
“We are solving the ‘Digital Dark Age,’” Peter Kazansky, an optical physicist at the University of Southampton in the United Kingdom who was uninvolved in the new work, told Gizmodo. “Our current records are kept on fragile magnetic platters that are constantly decaying; this research ensures our digital heritage becomes permanent.”
The science behind CDs
Silica is an advanced optical storage technology that physically alters a surface with light beams to encode data. For example, movies on a DVD are engraved onto the disc surface with laser technology for DVD players to decode. However, rapid advances in cloud and digital technology quickly phased out physical storage options, at least for the general public.
“But there was always talk of how optical storage could be used for commercial-level or industry-level archival storage,” James Chon, an optical physicist at Swinburne University of Technology in Australia, explained to Gizmodo during a phone call.
Chon, who wasn’t involved in the new work, took part in research that experimentally demonstrated the feasibility of harnessing the physical properties of light as an extra “dimension” for data storage. Chon and his then-colleagues at the University of Southampton used femtosecond lasers—extremely quick pulses of light—to fabricate glass material for encoding information.
Kazansky’s team further developed this technology in the following years—even sending a glass-etched version of Isaac Asimov’s Foundation trilogy to space—until it caught the attention of Microsoft researchers.
“We realized that if we could tame the physics and scale it, there was the potential for [laser-modified glass] to be disruptive as an archival storage technology,” Richard Black, Project Silica’s research director, told Gizmodo during a phone call.
A glass to last a lifetime
Project Silica began around eight years ago, with a multidisciplinary team of mechanical and electronic engineers, computer scientists, and optical specialists. To identify consumer needs, the team held lengthy discussions with organizations like the National Archives, museums, and the entertainment industry.
“These are organizations [with] very high-value data that they want to keep for a very long time,” Black said. They “care very deeply about the type of media that their data is kept on—the idea that there is no malware bug, state-sponsored actor, or whatever that can go in and change the archive,” he added.
Existing options, such as magnetic-tape data storage, did offer that to an extent, but they all eventually wear out, Black noted. In short, what those organizations desired was media that could survive “benign neglect,” or that “you can just put it on the shelf and forget about it,” Black explained.
Finding the optimal dimension
Silica’s primary innovation lies in its novel modification technique, which the team calls the phase voxel. Contrary to Southampton’s blueprint, phase voxels use differences in the phase of light wavelengths to record data in voxels, or a three-dimensional equivalent of a pixel. It only takes a single “zap” of the femtosecond laser to engrave the voxels onto the glass surface.
An image of the writing equipment for encoding data onto the glass surface. © Microsoft/Project Silica
For the demonstration in the paper, the team inscribed 301 voxel layers, but the glass chip has the capacity to store 4.8 terabytes of data—equivalent to about 2 million printed books or 5,000 ultra-high-definition films, according to an accompanying News & Views.
Finding the best approach was a series of trial-and-error experiments that sometimes took unexpected turns, Black said. For instance, unlike Southampton’s blueprint, Silica operates in four dimensions (the physical voxel plus phases of light) as opposed to five.
“That’s counterintuitive, but going four was better than five,” Black said. The decision improved energy efficiency and the overall capacity for packing in denser datasets, he added.
From your kitchen to libraries
Silica is also primarily borosilicate glass, a material found in most kitchens. It’s the stuff most Pyrex products are made of and the semi-transparent cover for oven doors.
Kazansky called the choice of material a “pragmatic engineering choice,” adding that he was “impressed by the scalability—the use of multi-beam writing and closed-loop feedback demonstrates a clear path toward industrial throughput.”
Chon also noted that Silica reflected a remarkable “amalgam” of numerous, smaller advances in optical engineering that “packs a whole lot of different, modern-day technologies for fast recording, reading, archival storage, and so on.”
Looking to the future of data
“One of the things that we’ve done with our research is effectively we have removed all of the scientific challenges—now, it’s only about the laser,” Black said. Given the relative simplicity of the modification technique, the remaining challenges lie mostly with the femtosecond lasers, which Black believes should see advances soon.
Already, however, the durability of Silica should offer huge benefits for researchers, engineers, and more, especially as we live in an era of information overload.
With Silica, users “can write the data into the glass, and then once it’s done, then it’s done—there’s no ongoing cost,” Black said. “And when we talk to people, that’s actually a really big change. This will change the way we think about keeping data and archival preservation.”
