holographic storage


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holographic storage

[¦häl·ə‚graf·ik ′stȯr·ij]
(communications)
A form of data storage in which bits of information are distributed throughout the storage volume and recorded interferometrically, rather than being stored at discrete locations in the medium.

holographic storage

A unique optical technology that records data as digital holograms in DVD-sized discs holding terabytes of data. Although research in holographic storage dates back to the 1960s, the first commercial product debuted in 2010 (see Tapestry). Whether this dramatically different technology has a future remains to be seen.

Two Lasers Write the Hologram
The first "data" laser is beamed through a matrix of LCD shutters, called a "spatial light modulator," into an optical region. The shutters are opened and closed based on the binary pattern of the data. For example, using a matrix of 1,000 by 1,000 bits, the data page would hold one million bits.

The second "reference" laser is angled into and intersects the data laser at the optical site. If the angle or frequency of the reference laser is changed, another hologram can be written into that area, overlapping and filling the exact same three-dimensional volume as the first hologram. Theoretically, thousands of pages can be written into the same optical space; however, the first commercial drive recorded 330 holograms.

One Laser Reads the Hologram
The page is read by directing just the reference laser back into the hologram. The light is diffracted into a copy of the binary data that is sensed by a matrix of CCD sensors. See micro-holographic, PRISM, HVD and optical disc.


The Spatial Light Modulator
Although this example uses cylinders as the optical medium rather than sections on a disc, the concept is the same. The LCD shutters are opened and closed to create the data page being stored.







The Interference Pattern
A unique interference pattern (the hologram) is created at the intersection of the two lasers in the optical material. To read the binary pattern, only the reference laser is used to output the data.







Early Prototype From IBM
The green laser beams are directed through lenses to the optical storage unit. The bottom magnification of the storage area shows the intersection where the hologram is created. The red arrow is the reference laser; the blue is the data laser. (Images courtesy of IBM Almaden Research Center.)


Early Prototype From IBM
The green laser beams are directed through lenses to the optical storage unit. The bottom magnification of the storage area shows the intersection where the hologram is created. The red arrow is the reference laser; the blue is the data laser. (Images courtesy of IBM Almaden Research Center.)
References in periodicals archive ?
2] and DMNA on the holographic storage characteristics, we found that some of the PQ and DMNA molecules bound to Zn[(MA).
Holographic storage systems have the advantage that they consume about one per cent of the power of equivalent magnetic disk storage and can operate without any special power conditioning or cooling--the servers holding 'cloud' data are now becoming so huge that they are being located close to hydroelectric installations to reduce the energy costs associated with cooling them.
Electronic media--particularly video--is the first application area targeted for holographic storage, but there are potentially significant benefits for any business that needs to digitally store videos, high-resolution imaging, or large amounts of data.
Although GE's holographic storage technology represents a breakthrough in capacity, the hardware and formats are so similar to current optical storage technology that the micro-holographic players will enable consumers to play back their CDs, DVDs and BDs.
This is truly a breakthrough in the development of the materials that are so critical to ultimately bringing holographic storage to the everyday consumer," said Lawrence.
General Electric says it's been working on holographic storage for six years, and through the new breakthroughs in storage, the company is eyeing to also produce more than 1TB of storage data.
Holographic storage media: the new disc type - called Tapestry(tm) - has a capacity of 300 gigabytes and is currently in its test phase.
Holographic storage HOLOGRAPHIC storage is real science fiction stuff, with lasers writing complex three-dimensional patterns to optical recording media.
Such patterned surfaces can be used in three-dimensional holographic storage, as optical filters for various angles or various wavelengths, as polarization separators, or as couplers into and out of the waveguides previously mentioned.
Holographic storage uses the whole thickness of a recording medium, rather than just the surface as CDs and magnetic media do, so storage densities are much higher and can be achieved in simpler geometries - no need for multiple platters, double sided disks or multiple layers as in DVDs.
Holographic storage will have to progress quickly to compete with existing technologies.