Holographic Memory

Definition and applications:

A 3-Dimentional information storage medium with multiple applications, and improved attributes. A photosensative medium, crystalline in nature, is used for the storage. A pair of laser beams are used to imprint an image in the medium at the intersection of the two beams. The frequency and angle of the reading beam are important in reading the information. This also makes it possible to record much more information at a given spot, simply by changing the angle of the reader beam. This presents a high-density possibility in which many "layers" of information can be recorded in the same place. It is postulated that this will expodentially increase the information saturation. For example, a sugar cube sized piece can store over 1GB of imformation. This presents many possibilities for the future of this information society.
 

Holographic Memory is a storage system which records information in the form of 3-D holograms.In a holographic storage system, information is stored in three dimensions, it has a much higher density compared to conventional storage devices such as jukeboxes or database storage. For example on a standard disk, if information is stored in 3 dimensions, a disk with a recording medium 1-mm thick holds more information than 100 compact disks of the same diameter. In applications which require large amounts of informations to be searched quickly, holographic memory provides a unique solution because of the high-speed access it provides. Traditionally, data would be searched one document at a time, but in holographic memory, each stored page of information is retrieved can be retrieved in parallel. The result is a read-out rate between 1 and 10 Gbits per second, and the random access time to a piece of inforamion can a matter of microseconds. This combination of high storage density, and speed makes holographic memory storage an ideal solution to applications which require larges amount of data, quick retrieval time, and a minimum amount of space. 

Market:

Holographic Memory is primarily in devlopment for computer related technologies. Many companies are looking at this for their own purposes, including IBM and Sony Corporation. Several government agencies are also devloping this technology. NASA believes that it can apply this new medium to their Space Program. Many of the armed service branches are also looking to this for many applications, including their training simulators. 

Illustration:

Major manufacturers:

Optitek, a company in the forefront of this emerging medium.
Optitek, Inc
1330 W. Middlefield Road
Mountain View, CA 94043
Phone: (415) 938-3300
Fax: (415) 938-3896

Holoplex, a start-up company that, among other technologies, is currently working on the Holographic Storage Medium.
Holoplex Inc.
600 S. Lake Ave. #106
Pasadena, CA 91106

Specifications and features:

Briefly, holographic memories use lasers to write (and later to read) "pages" of binary data on "planes" of a crystal. These planes could be seen as very thin slices on which a pattern is written. Because the technology uses planes, data is written a page at a time, rather than a bit at a time, with the result that the data can be read back at a much faster rate of speed than today's disk technology. Not only is the retrieval rate faster, but holographic technology allows much denser storage of data. The crystals used are clear, allowing the read and write lasers to ignore most of the planes or pages in the crystal and read the one page they want. It's as if you had a stack of papers and could read any page in the stack without having to move any of the other pages. And the amount of data that can be stored is amazing. According to the article, holographic technology could be used to store as much as 200 times as much data as a comparably sized CD-ROM. And the transfer rate is mind-boggling. One system already built has the capacity of "approximately half that of a CD" (say, 300 megabytes?), with the ability to transfer its entire contents in one second!

Pricing:

There is no current market price for this technology. The consumer versions of this, if any are currently available, are still in the R&D phase of their release. Estimates for release time range from the next year, to the year 2010, so it's really anyone's guess when this technology will become available to the average consumer market.

 

Brief history:

In recent years substantial progress has been made to implement such memories. Dr. Lambertus Hesselink will discuss recent advances in this technology at the February 20 meeting of the Santa Clara Valley Magnetics Society. In his talk Dr. Hesselink will review fundamental concepts related to materials, components, and system architectures. Tradeoff issues will be highlighted; the relationship between system architecture and applications will be discussed. Recent experimental results involving storage and retrieval of digital video will be presented. Lambertus Hesselink received BS degrees in applied mechanics and applied physics from the Twente Institute of Technology and MS and PhD degrees in the same disciplines from the California Institute of Technology. From 1977 to 1980 he was an instructor at the California Institute of Technology after which he joined the faculty of the Department of Aeronautics and Astronautics at Stanford University. He currently is a professor in the Department of Electrical Engineering at Stanford. His research interests include nonlinear optics, optical phase conjugation, optical data storage, optical computing, optical diagnostics, and visualization of scientific data. He has extensively researched photorefractive materials, optical interconnects, optical signal processors, and fast tomographic imaging. His research group demonstrated the first fully digital holographic data storage device. In 1994, Professor Hesselink founded Optitek to commercialize holographic data storage. He is co-principal investigator of the PRISM and HDSS programs funded by ARPA and administered by NSIC.

Market penetration:

Again, this technology is not yet available to the average consumer. I'll post information as it is available.

 

Latest developments:

November 1995 issue of Scientific American

Advantages and benefits:

This medium has many practical benefits. It allows a much greater amount of information to be stored in a much smaller space. The design of the storage techniue creates a copy of the digital datat that was implanted in it. Also, the technology for reading the medium requires mo moving parts. The ability of this medium to store information adjacent to pre-recorded information allows for much faster seek times, and transfer rates.

 

Downsides or negative impacts:

The only downside, as of yet (keep in mind that it is still in the devlopment stage), is that the current mediums are not able to be saturated with information to the extent that projections had expected. New mediums and small changes in storage and retrieval techniques are being explored. As of yet, the small advantages in storage and information exchange are not great enough to make it economical for the average consumer. The groups researching this technology, however, seem highly confident that, in the near future, the answers that they have been searching for will be found. There is another downside to this storage medium, it can only, as of yet, store images in grayscale. We'll see if this problem is rectified. If it is not, then, I venture to say, that for consumer purposes, this technology will either flop, of produce revenues far delinquent of projected goals.

Newsgroups and listervs:

Provide information about any newsgroups or listservs devoted to the product or technology.

Regulatory concerns:

No regulatory concerns, this is simply a new form of storage media that has possible applications in many different fields of the telecomunications community.

 

Bibliography and references: