Optical data storage has virtually unlimited lifetime

February 4, 2014 by Lisa Zyga, Phys.org feature
In the optical data storage system, data is stored in nanogratings created by ultrashort pulses from a femtosecond laser. The storage lifetime is about 3 x 1020 years at room temperature. Credit: Zhang, et al. ©2014 American Physical Society

(Phys.org) —Data stored on today's CDs and DVDs has a lifetime of several decades before the physical material begins to significantly decay. Researchers are working on prolonging the lifetime of stored data, but so far reaching even 100 years has been challenging. Now in a new study, researchers have demonstrated a data storage technique that has a lifetime of about 3 x 1020 years at room temperature—virtually unlimited—which could lead to a new era of eternal data archiving.

The researchers, Jingyu Zhang, Mindaugas Gecevičius, Martynas Beresna, and Peter G. Kazansky at the University of Southampton in the UK, have published a paper in a recent issue of Physical Review Letters on the new data storage technique.

"In the fifth decade after the invention of the Internet, more and more data is generated in this Information Age," Zhang told Phys.org. "How to store the data while considering the physical decay of storage materials and techniques has attracted much attention. Many individuals, companies and governments are interested in eternal data archiving to store data for military, science, and confidential purposes. Some applications can already be seen in the market; for example, M-disc and others are still under development. There is also a disc by Hitachi which lasts millions of years. We believe we are presenting the ultimate solution for eternal data archiving."

As the scientists explain, there is a general tradeoff in data storage between lifetime and capacity, so that media that store larger amounts of information tend to have shorter lifetimes. For example, physicists have demonstrated the possibility of storing vast amounts of data with individual atoms, yet the storage time is a mere 10 picoseconds at room temperature.

The new technique presented here provides both excellent lifetime and capacity. To record data, a femtosecond (fs) laser delivers ultrashort (280-fs, with 1 fs = 10-15 seconds) light pulses onto a piece of quartz. The light pulses create nanogratings—tiny dots—in the quartz, with each dot carrying three bits of information. This triple storage is possible because the laser performs multilevel encoding, so that the dots encode the intensity and polarization of the light in three layers of the quartz. Applying this technique, a disc the size of a CD or DVD with about 1000 layers has a data capacity of hundreds of terabytes, compared with hundreds of megabytes for today's commercial discs.

Arrhenius plot of the nanogratings decay rate at different temperatures. Black dots indicated measured values; red dots are calculated values. At a temperature of 462 K, the nanogratings would last for the current lifetime of the Universe. Credit: Zhang, et al. ©2014 American Physical Society

To determine the lifetime of the optical data system, the researchers subjected the information to accelerated aging to obtain the decay rate. The underlying mechanism of decay is the collapse of nanovoids that exist between the nanogratings; when the nanovoids collapse, the nanogratings become unstable and lose their stored data.

The researchers calculated that the decay time of the nanogratings, and thus the lifetime of the system, is about 3 x 1020 years at , indicating unprecedented high stability. The lifetime decreases at elevated temperatures, but even at temperatures of 462 K (189° C, 372° F), the extrapolated decay time is 13.8 billion years, comparable to the age of the Universe.

Previous optical recording methods have worked similarly to this one, except that the recording procedure used by these methods is so slow that it makes real-world applications unviable. The new method increases the data recording rate by 2 orders of magnitude by eliminating the need for the half-wave plate (which controls polarization) to be rotated. This rotation takes a relatively long time and reduces writing speed. By adding a matrix to the half-wave plate, the researchers enabled motion-free polarization control, greatly increasing the writing speed.

In the future, the researchers hope to make further improvements to the system, such as by improving the capacity by increasing the number of polarization states and intensity states to be exploited. They also plan to further increase the writing speed from its current rate of 6 KB/s to 120 Mbit/s by increasing laser power, among other means.

Explore further: More data storage? Here's how to fit 1,000 terabytes on a DVD

More information: Jingyu Zhang, et al. "Seemingly Unlimited Lifetime Data Storage in Nanostructured Glass." PRL 112, 033901 (2014). DOI: 10.1103/PhysRevLett.112.033901

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17 comments

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ab3a
5 / 5 (1) Feb 04, 2014
While 3E20 years may seem like a lot for one bit, remember that this is a thermal average calculation. Divide by 1E14 and you get the error rate for the media (assuming a 100 TB disk). This is still quite impressive. However, it is important to keep it in perspective.
Osteta
Feb 04, 2014
This comment has been removed by a moderator.
EarthlingX
5 / 5 (1) Feb 04, 2014
I hear about this multi year longevity of data burned on dvds, but my experience is not so positive. I burn all my dvds with verify check, so when they are burned, they can be read, but after a couple of years i can throw most of those dvds/cds in trash.
I changed a couple of burners and different media with same results, so talking about multi ten years life of dvd burned data doesn't go that well with my experience.
rkolter
5 / 5 (2) Feb 04, 2014
I really like this one and gave it five stars. But keep in mind, the fact that they've created a data scheme that might retain data at room temperature for 3e20 years and at oven temperatures for 14 billion years doesn't mean that the MATERIAL will survive.

The fact that the data survives past the lifetime of the material is neat, and begets the question what could you potentially encode the data on, and where could you put it to last as long as possible.

But... with supervolcanos blowing off about once a million years, devestating impacts every 50 million years or so, entire continents moving about, forming mountains that rise and erode away in 100-200 million years, the next few dozen ice ages, the eventual swelling of the sun to encompass Earth's orbit, the loss of our magnetic field once the core cools, and the final destruction of the universe itself in a big rip or collision of branes in shorter timescales... I just don't see the CD making it to the end.
_etabeta_
5 / 5 (2) Feb 05, 2014
"The storage lifetime is about 3 x 1020 years at room temperature" 3 x 1020 years?? Who proofreads for you?
antialias_physorg
3.7 / 5 (3) Feb 05, 2014
"The storage lifetime is about 3 x 1020 years at room temperature" 3 x 1020 years?? Who proofreads for you?

Physorg copy/pastes from other sources. Formatting gets lost. It happens a lot here.
If you want to read the original just copy/paste any sentence of the article into google.
russell_russell
not rated yet Feb 05, 2014
"To determine the lifetime of the optical data storage system, the researchers subjected the information to accelerated aging to obtain the decay rate. The underlying mechanism of decay is the collapse of nanovoids that exist between the nanogratings; when the nanovoids collapse, the nanogratings become unstable and lose their stored data."

Bad first sentence. Information does not age or have a decay rate.
All readers know 'storage' is the word meant, not 'information'.

holoman
not rated yet Feb 05, 2014
Okay, slow.
mzso
not rated yet Feb 06, 2014
Too bad it's made of quartz, which is brittle. So the storage is only durable until it falls.
Couldn't they use something more durable like sapphire?
Osteta
Feb 06, 2014
This comment has been removed by a moderator.
rkolter
not rated yet Feb 06, 2014
...3 x 1020 years?? Who proofreads for you?


Yeah. I read that and thought - WOW. That's big. That's too big. It has to be too big.
Skepticus
not rated yet Feb 07, 2014
The only truly eternal storage medium is the barbarians' clubs. Mind you, please encode the information on the handle part.
Eikka
not rated yet Feb 07, 2014
I hear about this multi year longevity of data burned on dvds, but my experience is not so positive.


It's called a lemon market.

A lemon market is where consumers can't trust or test the quality of products, so they have to assume all products are of average quality. Higher quality products get a competetive disadvantage for being more expensive and gradually the average quality of products drops with the dissapearance of the more expensive models.

In other words, no-one trusts a DVD-R to last more than a couple years, and few are willing to pay any extra for better discs with better quality control because they simply can't trust that they are. In reality not even the company itself can make sure all their discs are actually as good as they claim because it would take decades to do so, and still wouldn't prove that the discs they're making afterwards are any good.
antialias_physorg
5 / 5 (1) Feb 07, 2014
Bad first sentence. Information does not age or have a decay rate.
All readers know 'storage' is the word meant, not 'information'.

Information is correct - as the number of bits stored (the storage) doesn't change at all over time. The information content diminishes (decays) as the individual bits tend to go into a uniform state over time.
winthrom
not rated yet Feb 09, 2014
So, as I understand it, we have discovered that chipping marks on rocks (quartz) will be a way to preserve our data. Seems like the Egyptians invented this idea about 3000 to 4000 years ago. The "write" data rate in those days was really bad, and it took us several hundred years to break their code. 5000 years from now, who will be able to decipher >>our<< hieroglyphics?
rkolter
5 / 5 (1) Feb 11, 2014
The only truly eternal storage medium is the barbarians' clubs. Mind you, please encode the information on the handle part.


If you encode your data on the business end in high relief mirror-reverse, you can rapidly duplicate the data on biological mediums; unfortunately even with high fidelity copying the lifetime of the material is quite limited by nature of the copying methodology.
russell_russell
not rated yet Feb 15, 2014
"...individual bits tend to go into a uniform state over time."
Yes. "tend to go into a uniform state [of disorder] over time". Entropy.
The "content" (information) does not "diminish" "(decays)...over time".
Information is incorrect - the storage responsible for the preservation of order changes.
Everyone except AP knows the word storage was meant and not information.

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