David L. Shenkenberg, firstname.lastname@example.org
NISKAYUNA, N.Y. – GE Global Research, the technology development unit of General Electric, has created a disc that is the size of a standard DVD yet can hold the equivalent of 100 DVDs’ worth of information.
The disc contains holograms similar to those you might find on credit cards. Not only can holograms be pictures, as in this example, but they can also be markings. When a holographic disc is being read inside a DVD or Blu-ray optical drive, a laser beam alights on the disc and bends according to the characteristics of the holographic markings.
Overlapping blue lasers record holograms in a GE microholographic disc. Courtesy of GE.
What the GE team has done is to make simple marks that are very small and that are incorporated into the whole disc, not just etched onto the surface. The team found that marks with diameters of 1 μm exhibited almost 1 percent reflectivity. When used with DVD or Blu-ray optics, this reflectivity is consistent with a storage capacity of 500 GB of data, which is equivalent to 100 DVDs or 20 Blu-ray discs.
“Now almost everyone has heard of the ‘format war’ that continues to exist between the two next-generation optical storage formats: Blu-ray Disc and HD-DVD,” wrote Brian Lawrence, the leader of the holographic storage program at GE, on a corporate blog. “Regardless of which one ultimately wins, these technologies are mature, and the industry is starting to shift focus to the next format.”
GE initially will be focusing on the commercial archival industry, followed by the consumer market. “The day when you can store your entire high-definition movie collection on one disc and support high-resolution formats like 3-D television is closer than you think,” Lawrence said.
The researchers achieved an important milestone in the laboratory, and they are working on their next goal: storing more than 1 TB, or 1000 GB, of data on a disc. However, to make money off this discovery, they need to incorporate the technology into products that can be mass-produced affordably.
Recording with nanorods
GE’s holographic technology could face competition from a method being developed at Swinburne University of Technology in Melbourne, Australia, under the leadership of professor Min Gu. The Swinburne method could store the equivalent of 2000 DVDs, or 10 terabytes of information, on a single disc.
The researchers used gold nanorods as their storage material. Accordingly, they patterned the nanorods on a surface. In the future, they will pattern the nanorods on an actual disc.
Gold nanorods are known to be sensitive to polarization and to emit various colors of light when hit with a laser, allowing the researchers to exploit these two properties or “dimensions.” In the past, the length, width and height of stacks of such recording materials, or the three spatial dimensions, have been varied. This is why the researchers are calling this technology five-dimensional. They plan to test various nanorods in the future. The researchers believe that the technology will be commercially available within five to 10 years.