Nanorods boost capacity

Disks with a storage capacity 2000 times that of current DVDs could be enabled, following research undertaken at Swinburne University of Technology in Australia. Researchers from the university's Centre for Micro-Photonics have demonstrated that nanotechnology can enable the creation of what are called 'five dimensional' discs with huge storage capacities. The researchers, including Peter Zijlstra, Dr James Chon and Professor Min Gu, used nanoscale particles to increase the amount of information contained on a disk exponentially. "We were able to show how nanostructured material can be incorporated onto a disk in order to increase data capacity, without increasing the physical size of the disk," Prof Gu said. Although current disks have three spatial dimensions, nanoparticles have allowed the researchers to introduce spectral and polarisation dimensions. "These extra dimensions are the key to creating ultra high capacity disks," said Prof Gu. The spectral dimension was created by inserting gold nanorods onto the disk's surface. Because nanoparticles react to light according to their shape, this allowed the researchers to record information in a range of different wavelengths on the same physical location. A further dimension was introduced using polarisation. When they projected light waves onto the disk, the direction of the electric field contained within them aligned with the gold nanorods. This allowed the researchers to record different layers of information at different angles. "The polarisation can be rotated 360°," Dr Chon said. "So, for example, we could record at 0° polarisation then, on top of that, we could record another layer of information at 90° polarisation, without them interfering." Some issues remain unresolved, such as writing speed, but the researchers believe the disks may be available commercially within 10 years.