Holographic Storage Begins To See The Light.

Holographic storage has been something of a storage holy grail for nearly 30 years. Lucent Technologies recently disclosed its progress in developing a viable holographic storage system using mostly off-the-shelf components.

In August, the technology took another step towards creating a commercially viable product when Imation signed on to jointly develop a viable medium for the technology. "Having seen the breakthroughs [Lucent has] made, [Imation] decided to go into this," Rusty Rosenberger, Program Manager for Optical Technologies in the Data Storage and Information Management Group at Imation said. "Initial products are expected to use media with a form factor similar to that of current 5.25-inch Magneto Optical media," Rosenberger said. "Storage capacities of up to 125GB per disc, and transfer rates of 40MB/sec are expected," Rosenberger continued.

Data is recorded one "page" at a time. An array of optical elements (that can be switched between a state representing a 0 or a 1) represents a "page" of data. A laser beam and a second "interference" beam focused on the array create a holographic interference pattern that is recorded onto a photopolymer on the disc. By varying the angle of the interference laser beam, multiple pages of data can be recorded onto the same physical space. The image of the page is retrieved using a laser beam and the retrieved image is detected using a CMOS optical array. The page image is then decoded back into data. Through the use of micromirrors that alter the angle of the laser beam used for reading from the disc, multiple page images can be retrieved from a single space on the media.

The photopolymer that is used for recording, as well as the design and implementation of the basic technologies, were developed by Lucent. Imation's role, as Rosenberger notes, is to take the basic technology developed by Lucent and "to reduce the [technological complexity] to manufacturability of the media, to do the testing and so forth [in order] to make this a real product." Although the technology is at a state where it's too early to predict when an actual product will become available, Rosenberger "believes this is going to happen."

Further, Rosenberger doesn't envision holographic storage "as a replacement for tape." Rather, he sees it "more as an augmentation to RAID." If all goes well, the collaboration between Lucent and Imation may result in the first commercially viable implementation of holographic storage, finally delivering on the science fiction of the '60s and '70s with a new millennium product.