With the explosion of data storage demand, we are in dire need of more energy-efficient, data storage devices with higher capacity and longer lifespan. The data storage devices we see today are primarily either disk drives like HDD or magnetic tapes, but HDDs are not energy-efficient and have lower lifespans whereas magnetic tapes have longer access latency and are prone to degradation.
In search of better alternatives, we went back to optical disks. They have low energy consumption and are non-volatile. Although they have a limit on their data storage capacity, if improved they can be a perfect alternative. This gave rise to a new contender for data storage in the future- 5D Optical Data Storage.
Let us take a look at the scope of this technology.
The Inspiration
Whether you are a fan of comic books and cartoons or not, I am sure you must have heard of Superman before. When you dive into the lore of Superman, you would see a fictional Memory Crystal often seen in the Fortress of Solitude which acts as a repository of Kryptonian knowledge.
This inspired researchers, to what if we also create a similar crystal structure for storage. That is how an idea from science fiction gave birth to real-world technological advancement known as 5D Optical Data Storage. This is also the reason that this technology was given the moniker of Superman Memory Crystal.
Why is it called “5D”?
Well, it is not like we are going to save data outside of the 4 dimensions of space and time. So how did the term “5D” come into the picture?
The disc itself has 3 Physical Dimensions. The other 2 dimensions refer to the Encoding Dimensions. While traditional optical discs rely on the presence or absence of pits, 5D optical storage utilizes the Birefringes property to create another way of how data is encoded.
By manipulating the polarization of the laser researchers can exploit the inherent birefringences of the nanogratings, it is possible to encode more data in the same layer without adding any additional layers.
Note: Imagine light as a wave traveling through a material. In most materials, like air or glass, the light wave will travel in a straight line. However, in birefringent materials, the light wave gets split into two separate rays that travel at different speeds and in a slightly different direction. This property of materials is called Birefringences or Double Refraction.
This is why the term 5D is used accounting for 3 Physical Dimensions and 2 Encoding Dimensions.
Understand with Analogy
Imagine you have a numeric combination lock with a dial that can be set to different numbers and a keyhole. In traditional optical media, you only have one type of key, let's say a silver key. Each time you turn the key, the lock either opens (representing a "1" or presence of data) or doesn't (representing a "0" or absence of data), based solely on the position of the dial.
Now, in 5D storage, you have a special lock that not only relies on the dial's position. It also depends on the color of the key you use. Instead of just a silver key, you have keys of different colors: red, blue, and green. Each color represents a different layer of data.
So, when you use the red key depending upon the numeric combination the lock will still open (1) or not (0). But this time a different area is opened in the lock. Now use the green key and a third section of data will open.
So, in short originally in traditional optical media, you had access to only one storage space. But in 5D optical Storage, you have access to multiple rooms to store data so you can store more data in the same media.
Working Mechanism of 5D Optical Data Storage
The basic working principle of 5D Optical Data Storage is based on its two major components a fused Quartz material and a Femtosecond Laser.
- Fused Quartz: With its incredible chemical and thermal stability, fused quartz acts as a perfect medium for inscribing data.
- Femtosecond Laser: A specialized laser that can emit small and powerful pulses of light at intervals in the range of femtosecond; that is a quadrillionth of a second (1 Femtosecond = 10-15 seconds). This allows high precision while creating nanogratings.
Encoding Data
The data is encoded in the quartz material to store it. This is done by.
- Laser Control: The laser is used to create nanometer size modifications within the quartz material to create a periodic structure called nanogratings.
- Layered Data Storage: Nanograting has different properties like its position, size, orientation, and birefringence. each of which represents a different layer of data. Hence, 1 nanograting can store up to 8 bits of data.
Decoding Data
To decode the data a similar smaller setup is used.
- The laser beam is focused on the desired location within the storage medium, and the reflected light is analyzed.
- The alterations created during the writing process affect the properties of the reflected light, allowing the encoded data to be read back.
- By analyzing the properties of the reflected light the data encoded can be reconstructed.
Advantages of 5D Optical Data Storage
5D Optical Storage has many advantages which is why, it has been extensively researched. These include.
- High Data Storage Capacity: 5D Optical storage has very high data storage capacity. Some research also suggests that it can hold up to 360 TB of data per disc. Although it may seem less when compared to the data storage capacity of DNA data storage or holographic data storage (can store petabytes of data per disc), it still far surpasses any of the present-day data storage devices including Helium Hard Drives.
- Extreme Durability: It is made up of fused Quartz which is chemically and thermally very stable. This provides it with very high durability. Some research has suggested that it can withstand an impact of half a ton of weight being dropped on it. Under normal circumstances, it can have a lifespan of 1020 years.
- Better Data Security: Since the data is physically engraved in the material, it is less prone to hacking and security threats.
- Sustainability: With its high storage capacity and long lifespan 5D Optical storage are more environment-friendly and sustainable data storage alternative.
Disadvantages of 5D Optical Data Storage
Just like any other tech along with advantages, 5D optical storage has some disadvantages also. These include.
- Complexity and Cost: Since, specialized lasers are required for precise write/read control, the complexity and cost of the technology are higher.
- Long-term Stability of Nanogratings: Although the fused quartz in itself is very stable and durable, more research needs to be done on the stability of nanograting.
- Read/Write Speed: The process of writing data into 5D optical storage and retrieving it may not be as fast as some of the traditional storage methods. Due to the need for precise control over several parameters, the reading and writing speed may be slower.
Future Aspects
The future of 5D Optical storage seems very bright.
- 5D Optical Data Storage is considered a very promising alternative for data storage for archival purposes.
- Extensive research has been going on in the rewritability of this technology so that it can be used for purposes other than just archiving.
- With the improvements being made in material science and laser technology we are getting closer to creating this novel tech.
- It has close similarities with Holographic Data Storage technology. As the technology keeps improving, we will see improvements in both of these technologies. Some research has already proposed using holographic techniques in 5D optical storage. We can even expect a hybrid technology that may use the properties of both of these technologies to create a far superior data storage device.
Conclusion
To conclude, we can say that 5D Optical Data Storage has immense potential that revolutionize the data storage industry. Although still in the infancy stage, its lucrative advantages make it worth researching and developing further.
I hope by reading this article your understanding of 5D Optical Storage has increased. If you liked the article, do share it.
References
- Wang, H. et al. (2022) ‘100‐layer error‐free 5D optical data storage by ultrafast laser nanostructuring in Glass’, Laser & Photonics Reviews, 16(4). doi:10.1002/lpor.202100563.
- Gu, M., Li, X. and Cao, Y. (2014) ‘Optical Storage Arrays: A perspective for future Big Data Storage’, Light: Science & Applications, 3(5). doi:10.1038/lsa.2014.58.
- Hong, J., Li, J. and Chu, D. (2023) ‘Modulation approach of arbitrary linear polarization states of optical fields using single-beam coding for next-generation optical storage in glass’, Optics & Laser Technology, 164, p. 109539. doi:10.1016/j.optlastec.2023.109539.
