“Five-dimensional” disks promise storage of 10TB

A team from Swinburne University of Technology in Australia said that by harnessing nanoparticles and a “polarization” dimension to existing technology, storage can be massively boosted without changing the size of a current disc. For the first time researchers from the university’s Centre for Micro-Photonics have demonstrated how nanotechnology can enable the creation of ‘five dimensional’ discs with huge storage capacities. The research is carried out by Mr Peter Zijlstra, Dr James Chon and Professor Min Gu.We described another principle for a dense data storage in one of our previous articles.
The researchers, who have signed a deal with Samsung Electronics, said the technique had allowed them to store 1.6 terabytes of data on a disc with the potential to one day store up to 10 terabytes. One terabyte would be enough to hold 300 feature length films or 250,000 songs.

“We were able to show how nanostructured material can be incorporated onto a disc in order to increase data capacity, without increasing the physical size of the disc,” Min Gu said in a statement. “These extra dimensions are the key to creating ultra-high capacity discs.”

The researchers created the color dimension by inserting gold nanorods – which form so-called surface plasmons when hit by light – onto a disc’s surface. Because nanoparticles react to light according to their shape, this allowed the researchers to record information in a range of different color wavelengths on the same place on the disc.

To create the ‘colour dimension’ the researchers inserted gold nanorods onto a disc’s surface. Because nanoparticles react to light according to their shape, this allowed the researchers to record information in a range of different colour wavelengths on the same physical disc location. This is a major improvement on current DVDs that are recorded in a single colour wavelength using a laser.

This allowed the researchers to record different layers of information at different angles. “The polarization can be rotated 360 degrees,” said James Chon in a statement. “So for example, we were able to record at zero degree polarization. Then on top of that we were able to record another layer of information at 90 degrees polarization, without them interfering with each other.”

Recent efforts based on holography have shown that up to 500 Gb could potentially be stored on standard DVD-sized disks. Holographic methods take all of the information to be recorded and encode it in the form of a graph showing how often certain frequencies arise in it. That means that the recording process is a complex, all-at-once, all-or-nothing approach that would be difficult to implement on an industrial scale.

By contrast, 5-D recording is “bit-by-bit”, like current CD and DVD writing processes in that each piece of information is read sequentially. That is likely to mean that recording and read speeds would be comparatively slow, but the approach would be easier to integrate with existing technology.

“The optical system to record and read 5-D is very similar to the current DVD system,” says James Chon. “Therefore, industrial scale production of the compact system is possible.”

Now that the method has been demonstrated in custom-made multi-layer stacks, the team is working in conjunction with Samsung to develop a drive that can record and read onto a DVD-sized disc.Dr Chon says that the material cost of a disc would be less than $0.05 (£0.03), but there are a number of advantages in moving to silver nano-rods that would bring that cost down by a factor of 100.

Some issues, such as the speed at which the discs can be written on, need further work but the scientists said their research could have immediate applications in a range of fields. On the other hand, the need for a greater data storage is growing along the new technologies. For instance, they could help store extremely large medical files such as MRIs as well as financial, military and security areas by offering higher data densities needed for encryption.