Optical Device Records in 5-D

Optical recording technologies such as DVDs soon could have 2000 times more storage capacity than is currently possible.

A new optical device created by Swinburne University of Technology colleagues Peter Zijlstra, Dr. James Chon and professor Min Gu records in five dimensions, thanks to tiny gold rods that form so-called surface plasmons when hit by light.

Current discs have three spatial dimensions, but by using nanoparticles, the researchers from the university’s Centre for Micro-Photonics were able to introduce a spectral dimension as well as a polarization dimension, creating huge storage capacities.

With the new technology on board, it’s thought the average DVD could store an enormous 1.6 terabytes (1000 gigabytes) of data.

“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,” Gu said. “These extra dimensions are the key to creating ultrahigh-capacity discs.”

To create the “color dimension,” the researchers inserted the gold nanorods onto a disc’s surface. Because nanoparticles react to light according to their shape, the researchers were able to record information in a range of different color wavelengths on the same physical disc location.

This is a major improvement over current DVDs that are recorded using a laser in a single color wavelength.

The researchers were also able to introduce an extra dimension onto the disc using polarization. When they projected lightwaves onto the disc, 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 polarization can be rotated 360 degrees,” Chon said. “So for example, we were able to record at 0 degrees 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.”

Some issues, such as the speed at which the discs can be written on, are yet to be resolved, but the researchers are confident the discs will be commercially available within five to 10 years.

The discs are likely to have immediate applications in a range of fields. They would be valuable for storing extremely large medical files such as MRIs and could also provide a boon in the financial, military and security arenas.

The research was supported by the Australian Research Council and was published in the journal Nature.

For more information, visit: http://www.swin.edu.au/