Researchers from the University of Southampton have developed a new data format that can densely pack 360 Terabytes of information into a single 1″ glass disk. The disks are much more resistant to damage than existing optical technologies, as 5D disks are estimated to be capable of lasting up to 13.8 billion years, if temperatures remain below 180 degrees Celsius. For storage that isn’t intended to be stored for millions or billions of years, the disks are supposedly safe up to 1000 degrees Celsius.
Traditional optical disks such as CD’s store information by creating tiny bumps on the disk, which reflect information when a laser is shined on it. A bump acts as a 1 in binary code, whereas an absence of a bump acts as a 0. Therefore, CD’s are limited by the 2 dimensional space of the disk that is written to. This information is stored on the surface of the disk(the shiny part), so they’re very easily damaged by any form of contact such as scratching. They also have a limited lifespan due to environmental factors such as exposure to oxygen and humidity, making them unfit for long term archiving of data that needs to last hundreds of years.
5D disks utilize nanogratings, tiny structures that manipulate the way light is reflected. Instead of only changing if light is reflected, the structures change how light is reflected. The 5 dimensions used are the x, y and z position of the nanostructures, the direction of the light, and the strength of the light refracted.
The writing process utilizes a high speed, highly precise femtosecond laser that creates 3 layers of dots which are only 5 micrometers(5000 nanometers) apart. These dots alter the way in which light travels through the grids, which allow it to be read by a microscope/polariser. The diagram below may help you visualize this concept:
Currently, the technology is in an experimental phase. Proof of concepts have been created, however the storage medium has not yet been commercialized. The laser devices needed to write to these disks are extremely expensive, so it’s unlikely to be seen by consumers any time soon. As research continues and the technology improves, it may be commercialized, and we may expect to see it used in datacenter environments for archiving purposes, as the density offered rivals any other storage medium currently in existence.
Perhaps the most exciting usage of this technology will be for securing records of all of humanity’s knowledge and greatest works. As a storage medium that is both highly dense and highly durable, it marks an important step towards ensuring crucial information is never lost.