A researcher has developed a new optical device using tungsten and silicon nitride so that it can safely keep the data up to one billion years.
Jeroen de Vries, the researcher from the University of Twente MESA+ Institute for Nanotechnology, Netherlands has developed this optical disc
Current hard disk drives have the ability to store vast amounts of data but last roughly ten years at room temperature, because their magnetic energy barrier is low so that the information is lost after a period of time. CDs, DVDs, paper, tape, clay and tablets and stone also have a limited life.
It is possible to conceive of a number of scenarios why we wish to store information for a long time. “One scenario is that a disaster has devastated the earth and society must rebuild the world. Another scenario could be that we create a kind of legacy for future intelligent life that evolves on Earth or comes from other worlds. You must then think about archival storage of between one million and one billion years,” according to researcher De Vries.
De Vries has developed an optical information carrier that can store information for extremely long periods of time, with each bit being written using etching techniques. The chosen information carrier is a wafer consisting of tungsten encapsulated by silicon nitride. Tungsten was chosen because it can withstand extreme temperatures. A QR code is etched into the tungsten and is protected by the nitride. Each pixel of the large QR code contains a smaller QR code that in turn stores different information. “In principle, we can store everything on the disc that we believe is worthwhile saving: for example, a digital image of the Mona Lisa. In this study we tested a digital copy of the chapter about this medium from my thesis”, says De Vries.
In order to prove that the data is still legible after millions of years, an ageing test is required to see if the energy barriers are high enough to prevent data loss. De Vries: “According to the Arrhenius model, the medium should keep working for at least 1 million years if it is heated to a temperature of 473 Kelvin (200 degrees Celsius) and kept in the oven for an hour.” After the test there was no visible degradation of the tungsten, and it was still easy to read the information. Things become complicated at higher temperatures. When heated to 713 Kelvin (440 degrees Celsius) it becomes a lot more difficult to decypher the QR codes even if the tungsten is not affected.
