Laser-written glass data storage

Also known as Project Silica, 5D optical data storage, Laser-written glass archive storage

Laser-written glass data storage encodes information as tiny marks inside blocks of glass using femtosecond lasers. Microsoft's 2026 Nature paper reports a system that could hold about 4.8 TB on a 120 mm square glass plate, but the lifetime claims of more than 10,000 years rest on accelerated tests and extrapolation, and no commercial product has been announced.

Research and prototypesDemonstratedReviewed 21 Oct 2026
AI illustration · Illustrative scene, not a photograph of the specific device or experiment.

In plain language

Glass data storage writes information inside a block of glass using extremely short pulses of laser light. Each pulse makes a tiny change in the glass, and many of these changes are arranged in stacked layers, like a very small three-dimensional pattern of dots. Because the marks sit inside the glass, they are not exposed to scratches or dust in the way a disk surface is.

To read the data, a microscope shines light through the glass and records how the marks change it. Software then turns these patterns back into files. The glass does not need power to keep its data, which is why researchers see it as a possible way to keep archives, such as film, medical or legal records, for very long periods. The technology is still at the research stage, and the claims about how long it can last are mostly based on tests and extrapolation rather than observed ageing.

Technical explanation

Femtosecond laser pulses are focused at a point inside the glass to create a voxel, a small region whose optical properties have been changed. Microsoft's Project Silica team describes a system called Silica. In fused silica it writes birefringent voxels, which change the polarisation of light passing through them. In borosilicate glass it writes phase voxels, which change the phase of light instead. Voxels are arranged in layers. The paper reports 301 layers for fused silica and 258 for borosilicate.

For the fused silica system, the paper reports a density of 1.59 Gbit/mm³ and about 4.84 TB of usable capacity in a 120 mm by 120 mm, 2 mm thick platter. Writing runs at 25.6 Mbit/s per beam, with an energy use of 10.1 nJ per bit. For borosilicate phase voxels, the reported density is 0.678 Gbit/mm³, giving about 2.02 TB on the same platter size, at 18.4 Mbit/s per beam (65.9 Mbit/s with four beams). These figures were obtained at a 10 MHz repetition rate, with a 516 nm laser and an NA 0.6 objective, and the densities depend on the voxel pitch and layer spacing used. The paper states that absolute read throughput was not considered in the study, and no read speed for a complete archive was found in the sources reviewed.

Lifetime was assessed by annealing borosilicate phase voxels at 440 to 500 °C, tracking the loss of diffraction efficiency, fitting a stretched exponential, and extrapolating with an Arrhenius model (activation energy 3.28 eV). The paper reports a modification lifetime above 10,000 years at 290 °C from this extrapolation, and it states that the test covers thermal stability only, not mechanical stress or chemical corrosion. Microsoft's 2026 blog states that data should last at least 10,000 years, without giving a temperature. An earlier University of Southampton press release from 2016 described five-dimensional encoding in fused quartz, using voxel position, orientation and size, and claimed 360 TB per disc. That figure has not been checked against a peer-reviewed paper.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Demonstrated Shown in a published experiment, test or shipping product.

The fused silica Silica system reaches a density of 1.59 Gbit/mm³ across 301 layers, giving about 4.84 TB of usable capacity in a 120 mm square, 2 mm thick glass platter.

Sources: [1] · Reported figures table

Borosilicate phase voxels reach 0.678 Gbit/mm³ and about 2.02 TB of usable capacity on the same platter size, which is lower than the fused silica result.

Sources: [1] · Reported figures table

Writing runs at 25.6 Mbit/s per beam for fused silica and 18.4 Mbit/s per beam for borosilicate (65.9 Mbit/s with four beams), at energy costs of 10.1 nJ per bit and 8.85 nJ per bit, under a 10 MHz repetition rate, a 516 nm laser and an NA 0.6 objective.

Sources: [1] · Reported figures table · medium confidence

The authors state that the lifetime test covers thermal stability only and does not account for mechanical stress or chemical corrosion.

Sources: [1] · Lifetime and accelerated ageing

In 2019, Microsoft and Warner Bros. stored the full 1978 film Superman, about 75.6 GB of data plus error-correction codes, on a 75 x 75 x 2 mm quartz glass piece and read it back. The article says the data was still readable after tests that included baking the glass in an oven at 500 degrees and scouring it with steel wool.

Sources: [4] · Proof of concept and durability test

Reported, unverified Stated by a company or team but not independently confirmed.

Accelerated annealing of borosilicate phase voxels at 440 to 500 °C, extrapolated with an Arrhenius model, gives a modification lifetime above 10,000 years at 290 °C in the paper. Microsoft's 2026 blog states that data should last at least 10,000 years, without a temperature.

Sources: [1], [2] · Lifetime and accelerated ageing · medium confidence

The University of Southampton reported in 2016 that femtosecond-laser five-dimensional storage in fused quartz could hold 360 TB per disc, withstand up to 1,000 °C, and retain data for a virtually unlimited period at room temperature, citing 13.8 billion years at 190 °C.

Sources: [5] · Press release, reported figures · low confidence

Microsoft says the Project Silica research phase is complete, but it has not announced a commercial product or release date for the technology.

Sources: [2] · Status · medium confidence

Limitations and open problems

  • The reported lifetimes come from accelerated annealing and extrapolation, and the authors state that the test covers thermal stability only, not mechanical stress or chemical corrosion.
  • The densities are the paper's best results on specific samples and voxel designs. The borosilicate density is less than half the fused silica figure.
  • No read speed for a full archive was found, the paper states that absolute read throughput was not considered, and the write figures are per beam. A 2019 Microsoft article says there is much more work ahead to reach that scale.
  • The 2016 capacity and lifetime figures come from a university press release rather than a peer-reviewed paper, and have not been independently checked.
  • Writing needs femtosecond lasers. Reading uses a microscope and camera, and Microsoft's 2026 blog describes a single-camera reader. No verified cost figures for media or equipment were found in the sources reviewed.

Possible future uses

Speculative

Ideas, not predictions. None of these has been demonstrated.

  • Cold storage of film, music and cultural archives where tape and disk migration is costly and recurring.
  • Long-term keeping of legal, medical and financial records that must stay readable for decades without power.
  • Deep archive vaults in remote or harsh locations, where the storage media does not need a continuous power supply.

Product concepts: Glass archive for libraries

Timeline

  1. 15 Feb 2016University of Southampton reports five-dimensional femtosecond-laser storage in fused quartz, claiming 360 TB per disc. Sources: [5]
  2. 2017Project Silica is featured in a Microsoft Ignite 2017 keynote. Sources: [3]
  3. 4 Nov 2019Microsoft and Warner Bros. report storing and reading back the full 1978 film Superman on a 75 x 75 x 2 mm quartz glass piece as a proof of concept. Sources: [4]
  4. 18 Feb 2026Nature publishes the Project Silica paper reporting fused silica and borosilicate results. Accelerated ageing tests in the paper extrapolate to a lifetime above 10,000 years at 290 °C. Sources: [1], [2]

Futures this could help bring about

AI illustration
How far away?

Storing the world's archives in DNA

Engineering prototypes · 4 of 7 steps done

Glossary

Voxel
A three-dimensional pixel, a small volume inside a material that stores one unit of data.
Femtosecond laser
A laser that emits pulses lasting about a quadrillionth of a second, which can change glass at a tightly focused point.
Birefringence
A property in which a material splits light into two polarised components that travel at different speeds, changing its polarisation.
Borosilicate glass
A heat-resistant glass made with boron oxide, used in cookware and laboratory equipment.

Sources

  1. peer reviewed paper
    Laser writing in glass for dense, fast and efficient archival data storage
    Microsoft Research Project Silica Team. Nature, 18 Feb 2026. DOI: 10.1038/s41586-025-10042-w. Accessed 21 Oct 2026.
  2. company announcement
    Project Silica's advances in glass storage technology
    Richard Black. Microsoft Research, 18 Feb 2026. Accessed 21 Oct 2026.
  3. company announcement
    Project Silica
    Microsoft Research, 2026. Accessed 21 Oct 2026.
  4. company announcement
    Project Silica proof of concept stores Warner Bros. 'Superman' movie on quartz glass
    Microsoft News, 4 Nov 2019. Accessed 21 Oct 2026.
  5. university press release
    Five-dimensional optical data storage in glass (University of Southampton news release)
    Professor Peter Kazansky. University of Southampton, Optoelectronics Research Centre, 15 Feb 2016. Accessed 21 Oct 2026.

Revision history

3 changes since this profile was created.

Changes on 21 Oct 2026
Published on owner instruction (content loop iteration 9)81096f5
Sources and claims re-checked against originalsfbb434c
Initial profile drafted from primary sources7e66249