May 23, 2009 Until recently, the idea of holding your entire collection of movies on a single super-sized DVD was the stuff of science fiction. According to Australian researchers at Melbourne's Swinburne University of Technology, advances in their study of nanoparticles have raised the possibility of storing vast amounts of data on the one disc in the not-too-distant future.

Three years into a five-year study, the researchers from the university’s Centre for Micro-Photonics estimate that the use of nanotechnology can boost storage capacity of a standard DVD 2000-fold, without increasing the size of the disc. Regular DVDs have three spatial dimensions, but the Swinburne team was able to introduce two additional dimensions for recording data – color and polarization.

The color dimension, which involves the color of light being used to write and read data, was created by inserting gold nanorods onto a disc surface. Nanoparticles react to light according to their shape, so this allowed researchers to record information in a range of different color wavelengths on the same physical disc location. A big step considering that DVDs are recorded in a single color wavelength – red or blue-violet – using a laser.

The polarisation dimension works by projecting light waves onto the disc and aligning the electric field within the light waves with the gold nanorods. This enabled researchers to record different layers of information at different angles. As the polarisation can be rotated 360 degrees, information is recorded at different degrees of polarisation without interfering with one another.

To put things in perspective, an average DVD disc is about 1.2mm thick, and the information recorded on a standard DVD takes up about one thousandth of a millimetre. This means that only 0.1 percent of the available volume is effectively being used.

While DVD technology also uses this technique (a double-sided DVD has four layers), the research shows that it is possible to experimentally increase the storage capacity to 52 layers, with further ability, researchers say, to go as high as 300 layers.

Although issues, such as the speed at which the discs can be written, still need to be ironed out, an agreement has been struck with Korean manufacturing giant Samsung. But Swinburne is not alone. Other big guns are also working on a super storage capacity disc, with General Electric recently announcing it was developing a high-volume holographic disc.

Expected to be commercially available within the next five-to-10 years, the discs would initially be targeted at fields that needed huge capacity, such as the medical, military and security industries.

Mick Webb