It is not a disk as such, but the unique silica parallelepiped created by Optica is about the size of a Blu-ray disc, but can store 500 TB, or 10,000 times more data than optical discs.
There had already been advances in so-called “5D” storage, but now reasonable writing speeds have been achieved and we are looking at a potential alternative for storing large quantities over the very long term: these “5D disks” are capable of withstanding a temperature of 1,000 °C and of lasting 13.8 billion years without degrading if they are at room temperature.
In this optical technology, each file is stored in three layers of tiny dots of a size on the nanometer scale. The position, size and orientation of each dot is part of its data storage, and each one changes the polarization of the light traveling through the disk: data reading consists of a microscope and a polarizer performing that task.
Although this type of storage system has been in development for some time, there was one major limitation: write speeds for storing such data were extremely slow, making this storage medium impractical.
However, the Optica researchers have used a laser that operates on the femtosecond scale and instead of writing directly to the disk crystal, it takes advantage of a physical phenomenon that creates tiny structures using a pulse of light, and improves on previous attempts to improve writing speed.
With this technique the Optica team was able to store 5 GB of text data on a silica disk that was the size of a conventional CD, and the accuracy of the operation was nearly 100%. According to their estimates, the write density of this method would allow about 500 TB of data to be stored, and the write speed would hover around 230 KB/s.
This is not a spectacular speed – a conventional hard disk is around 80-100 MB/s – but this technology has a fundamental advantage: it is a great alternative for storing data for not years, but millions of years.