Researchers at Shanghai University of Technology have created an optical data bus that can store 200,000 gigabytes of data on a disc the size of a DVD or Blu-ray disc. A storage space of this size would hold approximately 40,000 DVDs, meaning the evening's program could cover a period of approximately one hundred and ten years.
The devices presented in Nature have 24 times the data density of the most advanced hard drives and 4,000 times the data density of the average Blu-ray disc.
Optical discs are durable and inexpensive, but their capacity is limited because data is recorded on them in a single layer. In order to overcome this limitation, methods have already been developed that allow data to be transferred to such a disk in several layers – the practical hurdle is that the write-read solution requires a complex optical system.
Chinese researchers reported that they were able to record data in a hundred layers. The applied point on the carrier medium – which means 1 or 0 suppression – is 54 nanometers, one-tenth of the wavelength of visible light.
The writing technology relies on two lasers: a green laser with a length of 515 nm starts the formation of the dot, and a red laser with a length of 639 nm stops it. By timing the laser application, it is achieved that the diameter of the resulting data point is smaller than the wavelength of the light creating it.
The reading also takes place in two stages: a 480-nm blue laser causes the dots to fluoresce, while a 592-nm orange laser “switches off” the fluorescent dots.
The key is the special material of the disc,
AIE-DDPR, which reacts differently to different wavelengths of light.
We have been searching for this material for 10 years. The difficulty was how the material responded to writing and reading, especially with 3D geometry
said Min Ju, a professor at the Shanghai Institute of Technology, who was surprised at how well nanoscale data storage was in the special new material.
By the way, AIE-DDPR is fully compatible with DVD mass production, producing a disc in 6 minutes.
A new disk-based data storage system can store exabyte-sized data in a single room instead of a stadium-sized space. Those who find this worryingly insufficient, the researchers are encouraged by the possibility of increasing the number of layers of recorded data with further development of carrier materials and optics.
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