What Is Holography and How It Works In Computer Storage?

Storage is seen by many in the computer industry as the critical enabling technology for many new multimedia applications. To address its rapidly increasing requirements is the key to bring forward this new technology.

The increased demand for more storage capacity, coupled with the development of wide variety of applications, have considerably taxed the ability of existing storage systems namely, optical and magnetic.

Whoever delivers a SOLUTION to the current storage capacity problem, will dominate the information storage market of the future...

A new optical technology, called "HOLOGRAPHIC STORAGE" may offer exciting possibilities, and the promise of being the most cost-effective solution of the storage requirements of multimedia computing than any existing or projected technology.

History of Holography

The theory of holography was developed by Dennis Gabor, a Hungarian physicist, in the year 1947. His theory was originally intended to increase the resolving power of electron microscopes. Gabor proved his theory not with an electron beam, but with a light beam. The result was the first hologram ever made. The early holograms were legible but plagued with many imperfections because Gabor did not have the correct light to make crisp clear holograms as we can today . Gabor need LASER Light. In the 1960s two engineers from the University of Michigan: Emmett Leith and Juris Upatnieks, developed a new device which produced a three dimensional image of an object. Building on the discoveries of Gabor, they produced the diffuse-light hologram. For more information, check the Research Paper

Today, we can see holograms, or 3-D images, on credit cards, magazine covers, art galleries. Yet this unique method of capturing information with lasers-the science of holography-has many more applications in the industrial world and is on the verge of revolutionizing data-storage technology as we know it.

Holography in Data Storage

Because holographic images have depth of field, information that is digitized into the computer language of zero' s and one' s can be layered deep inside a hologram. Holographic storage is much different form conventional methods of storing digitized data . Magnetic and optical disks line up data digit by digit on flat, single layer tracks. Holographic data storage, in the other hand, can stack about 40 pages or arrays of digits, using the depth of the medium. Pages deep in the hologram can be read by tilting the angle of the light beam used to read it. To the user, this could mean that drives that fit in tomorrow' s portable computers could store several gigabytes of data and retrieve that information nearly instantly. at prices equal or lower than the cost of today's hard drives.

However, from my own research and the excellent reviews on holographic data storage that have been published, from the technological and commercial point of view, one gets the impression that holographic technologies, though very fascinating, had not reached a stage of maturity sufficient to pose a threat to other types of memories. In fact, besides all the favorable developments and the conceptual richness of holography itself, digital holographic stores have a major remaining problem area of developing a good storage material. Dr. T.C. Lee, Director of optical engineering at Tamarack Research said "we have developed all the bells and whistles to make a drive, but the media is far away." The ideal material will have a high signal to noise ratio so that data can be found and read quickly without having to flood the holographic media with so many photons that it gets hot or consumes a lot of laser power. In order to confirm data, the medium also needs to be very sensitive to light and be stable enough so that holographic fringes do not move inside.