5-D Discs to Store 2000 Times More Than DVD

Researchers from the Centre of Micro-Photonics at Swinburne University of Technology have shown how discs, with storage capabilities of 2,000 times the size of a DVD, can be developed using nanotechnology. Their findings point towards using nanoscopic particles to exponentially boost the amount of information stored on a single disc with a unique ‘five dimensional’ structure.
 Transmission electron microscope (TEM) image of gold nanorods used for spectral encoding (Credit: Swinburne University of Technology)
Transmission electron microscope 
(TEM) image of gold nanorods 
used for spectral encoding 
(Credit: Swinburne University of Technology)

“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,” said Professor Min Gu, one of the researchers on the team. Conventional discs have three spatial dimensions, but in this new process, an extra spectral or color dimension as well as a polarization dimension were added using nanoparticles. These two extra dimensions are the imperative additions in developing ultra-high capacity discs.

To fabricate the ‘color dimension’, gold nanorods are interleaved into the disc’s surface. The information can then be recorded in a range of different color wavelengths on the same physical disc location. This is possible due to a unique characteristic of the nanoparticles, which react differently to light depending on their shape. Current DVD discs can only record in a single wavelength of color.

The other dimension was added onto the disc using polarization. The team at Swinburne standardized the alignment between the electric field and gold nanorods by projecting light waves onto the disc. This enabled a combination of data to be stored at different layers of the disc and at different angles. Since the polarization of the stored data can be rotated 360 degrees, information can be recorded at zero degrees polarization all the way up to 360 degrees without any interference between layers.

 Illustration of multilayer polarization encoding in a photorefractive polymer doped with semiconductor nanocrystals (Credit: Swinburne University of Technology)
Illustration of multilayer 
polarization encoding in 
a photorefractive polymer 
doped with semiconductor 
nanocrystals (Credit: Swinburne 
University of Technology)

The researchers do mention that an important issue to consider would be the cost of such technology, which requires the usage of gold nanorods. However, it is hoped that by moving to silver nanorods, the price could be reduced by a factor of 100.

Since the new technology is still at infancy, some issues are yet to be resolved, such as the write-on speed of the discs. The developers predict that the device will become commercially available within five to ten years, noting that such discs could be used for storing extremely large files such as medical and financial records.

TFOT has previously written on a research conducted at the University of California, according to which it would be possible to store the equivalent of 250 DVDs on a device the size of a small coin. You are also welcome to check out our article about mempile – a terabyte CD based on a revolutionary optical-storage technology currently under development, according to which it would be possible to store an equivalent of 250,000 high-quality MP3s or more than 115 DVD-quality movies and about 40 HD movies on a single CD-sized medium. Be also sure to check out our article about nanowires which make high capacity storage devices that may become a key factor in next generation high storage magnetic devices.

Additional information on the new disc technology can be obtained at Swinburne University of Technology’s website.

Icon illustration by Kristian Molhave.