How can humanity’s huge amounts of data be reliably stored in the long term? While previous storage media such as hard drives and magnetic tapes become unusable after just a few decades, laser-treated glass could provide stable storage for many millennia. A team at Microsoft Research has now developed a system with which information can be efficiently written to glass and read out again. Almost five terabytes of data can fit on a single twelve by twelve centimeter glass chip.
Never before has humanity produced as much data as it does today. Much of this data needs to be retained for decades or even centuries because it has great personal, legal, commercial or scientific value. However, today’s data carriers such as hard drives or magnetic tapes lose their function after just a few decades, meaning that the data has to be transferred to new storage media regularly, which takes a lot of time and energy. Researchers are therefore looking for ways to keep information safe in the long term.
Dots in the glass
A research team at Microsoft Research has now developed a system called Silica that can store data efficiently and permanently in glass. A so-called femtosecond laser uses extremely short, high-energy laser pulses to engrave tiny patterns into a plate made of durable quartz or borosilicate glass. The information is encoded in the form of voxels, i.e. three-dimensional pixels – tiny dots in the glass that each store a bit of data due to their position and orientation. The individual voxels are so small and so close together that there is space for 301 layers in a two-millimeter-thick glass plate. In an area measuring twelve by twelve centimeters, 4.8 terabytes of data can be stored – as much as around two million printed books or 5,000 ultra-high-resolution 4K films.
A laser can generate ten million pulses per second and write one voxel with each pulse. With four lasers working simultaneously, the researchers achieved top speeds of up to 65.9 megabits per second. The data can be read out line by line using an automated microscope. In order to keep the error rate as low as possible, an algorithm based on machine learning checks the data points for plausibility and corrects possible reading errors if necessary. For additional security, the research team also suggests optimized redundancy: important data is stored multiple times in different locations on the data carrier so that it can be reconstructed if parts are damaged and are no longer readable.
Resistant for thousands of years
To test the durability of the glass chips, the researchers simulated accelerated aging. To do this, they repeatedly heated the engraved glass plates to up to 500 degrees Celsius. “Our tests indicate an exceptionally high long-term stability,” reports the team. “The data stored in the glass remained accessible even after 10,000 years at 290°C and probably significantly longer at room temperature.” The glass is also insensitive to moisture and electromagnetic interference. The team did not take into account the possibility that the glass could be broken down by chemicals or broken by mechanical stress. However, the types of glass used – quartz glass and borosilicate glass – are significantly more break-resistant than normal window glass, for example.
“Silica combines performance, durability and practicality, transforming a laboratory concept into a viable solution for preserving the records of human civilization,” write Feng Chen and Bo Wu of Shandong University in China, who were not involved in the study, in an accompanying commentary in Nature. According to Chen and Wu, the system is best suited for storing so-called “cold data” – that is, data that needs to be stored for a long time but not updated regularly. Because once written in the glass, the voxels can no longer be changed.
“In the long term, the development of compact, smartphone-friendly readers and writers could unlock the true potential of the technology,” say Chen and Wu. According to Microsoft’s silica project team, conventional lasers could also be used for data storage in glass – albeit with significantly reduced performance. “If implemented on a large scale, silica could represent a milestone in the history of knowledge storage, similar to oracle bones, medieval parchment, or the modern hard drive,” write Chen and Wu. “One day, a single piece of glass could carry the torch of human culture and knowledge for millennia.”
Source: Microsoft Research Project Silica Team (Cambridge, UK), Nature, doi: 10.1038/s41586-025-10042-w