Super discs made in China! One can fit a small data center

Cressy from the temple of Wafei

量子位 | 公众号 QbitAI

A single disc can fit a small data center, and the limit of disc capacity has ushered in a major breakthrough!

This is the largest capacity "super disc" in history created by Chinese scientists over a period of seven years:

The "Super Disc" is jointly created by the Shanghai Institute of Optics and Mechanics, the University of Shanghai for Science and Technology and other institutions, and its capacity has reached tens of thousands of times that of ordinary Blu-ray discs.

Not only is the capacity considerable, but also secure, reliable, and long-term storage, making it ideal for long-term, low-cost storage of massive amounts of data.

If mass production is realized, using this kind of optical disc as a storage array is expected to build an exabyte-level high-density data center in a single room space.

Related studies have been published in Nature:

In this regard, some netizens commented that scientists have worked really hard to ensure that your hard disk resources can be passed on to your great-great-great-grandchildren in good condition......

So, how strong is this "super disc"?

Engrave data at the nanoscale

In terms of storage capacity, its maximum equivalent capacity has reached 1.6Pb, which is more than 1,600 Tb or nearly 1.68 million Gb.

The maximum capacity of the hard disk that can be found on the e-commerce platform is only 20TB (160Tb), which is only 10% of the "super disc".

This capacity can store about 3000 hours of 8K movies at a high bitrate (160Mbps).

In this regard, Gu Min, a foreign academician of the Chinese Academy of Engineering, also explained with the popular ChatGPT:

Take the deep learning model GPT as an example, its entire internet text size is about 56 petabytes.

If you use the 1TB capacity of the 1TB portable hard disk that is widely used for storage, it needs to occupy the area of a playground when spread out.

The new 3D nanophotonic storage (the technology used in the "super disc") can save storage space to the size of a computer.

Even when the capacity is divided into unit areas, it achieves a data density of 26 terabytes per square inch (6.45 square centimeters), which is 23 times more than the best hard drives.

The "Super Disc" is only 1.2 mm thick, but it is stacked with 100 layers of thin film media, and has an ultra-high resolution of 54 nm dot size and 70 nm channel spacing.

While the dot size of ordinary optical discs is close to the order of micrometers (1000 nanometers), the "super disc" can be described as engraving data on the nanoscale.

In terms of lifetime, the researchers performed accelerated aging tests on the fluorescence attenuation of the recording points at 130 and 120 degrees Celsius.

At both temperatures, the decay time of the fluorescent information is 12 and 26 hours, respectively.

Based on this, the researchers estimated that the data in the "super disc" can be stored for more than 41 years based on the Arrhenius model, and the life span can be further extended if a protective layer is added.

Moreover, the "Super Disc" not only achieved a leap in the capacity of storage devices, but also an important breakthrough in the field of optics.

In the 19th century, physicist Ernst Abbe proposed the concept of "diffraction limit", that is, an optical system can resolve the minimum distance between two close points without other aberrations or technical limitations.

According to Abbe's theory, the diffraction limit d = 1.22λ/2NA, where λ is the wavelength and NA is the numerical aperture of the system, and the information point spacing of the "superdisc" is less than the theoretical value calculated according to this formula.

So, how did the researchers come up with this "super disc"?

Stacking 100 layers of film material

At the heart of the "Super Disc" is a thin film material called AIE-DDPR, which is obtained by doping a polymerization-induced luminescence dye in a photosensitive resin.

The material has high transparency and homogeneity, and can be optically stimulated by femtosecond laser beams for nanoscale polymerization and deactivation.

AIE dyes exhibit enhanced fluorescence emission in the aggregated state, in contrast to the fluorescence reduction of many traditional fluorescent dyes upon aggregation, allowing the film to produce a strong fluorescence signal when excited by a laser beam, such as for data reading and detection.

In addition, AIE-DDPR has the advantages of high storage density, environmental friendliness, durability, and compatibility with existing optical disc manufacturing processes.

First, a photosensitive resin (DTPA, dipentaerythritol pentaacrylate) is mixed with a photoinitiator (ITX, i.e., 2-isopropylthioxanthone) and an AIE dye (HPS, i.e., hexephenylthiarole) in an organic solvent.

This mixture is then stirred on a hot plate to ensure thorough mixing, then heated in an oven to remove solvents, and then the mixture is spin-coated onto a transparent substrate.

The coated film needs to be cured under UV light to form a uniform and transparent film. The curing process removes the solvent and allows the resin to be cross-linked to form a solid film.

Once the thin film is formed, the data can be written, and here the researchers are using a dual-beam laser system.

First, a femtosecond laser beam with a wavelength of 515 nm is used to focus on the thin film, and a polymerization reaction is initiated by two-photon absorption, forming a recording point.

Then, deactivation is performed using a continuous wave (CW) laser beam with a wavelength of 639 nm to suppress the aggregation of the surrounding area, resulting in super-resolution recording points.

This is the key to the "super disc" being able to break through the diffraction limit.

Ultimately, the researchers stacked 100 layers of AIE-DDPR film vertically, maintaining a certain spacing between each layer, to achieve higher storage density in a limited space.

One More Thing

When it comes to increasing data storage density, human exploration never stops.

Before the advent of the "Super Disc", the disc with the largest capacity was the "5D Disc" made by British scientists out of glass in 2013.

In terms of interdisdisciplinarity, some biologists have tried to use DNA as a storage carrier for information, and successfully "stored" the information into E. coli.

Entering a new era of AI explosion, artificial intelligence may also provide new ideas for finding higher-density storage media.

Address:

https://www.nature.com/articles/s41586-023-06980-y