How Holographic Versatile Discs Work ?

Holographic memory technology is not new. Developers have offered the improved storage capacity of this method that surpasses CD and DVD storage limits. Not only that, movement of data is much quicker and more efficient. The holographic method transfers data 40 times faster than the best DVD. Yet holographic versatile discs have yet to become the standard in commercial electronics. Why? Cost is one key factor. The complexity of establishing and using a complete system is another limitation.

Holography is at the heart of this unique memory-storage method. Holography records patterns of light and produces an object in three dimensions. This visible image is known by the name “hologram.” Holography wouldn’t be possible without a laser light beam split into a reference beam and the information beam. This latter beam passes through an image and takes the information about that image in light waves. When the two beams meet there is light interference at the intersection. This is recorded on a photosensitive disc.

Accessing this information means directing the beam to the hologram. The light pattern is retrieved and can be recreated elsewhere. The major difference between recreating a visible hologram is that in memory storage the holographic information is stored in digital form. The light and dark areas correspond to 1s and 0s in binary/digital method. This method can increase the amount of data stored from several gigabytes to 1 terabyte or more. Most detailed information about the holographic versatile disc indicates that the recording layer is thicker than on a DVD, for example.

One of the technical problems in making holographic versatile disc systems affordable lies with the complex systems necessary to get the laser beams aligned for accuracy. For this technology to work well the beams of light must intersect perfectly. Currently, the two beams are directed toward the image at different angles. Newer experimental technology focuses on sending the two beams on the same line, which means they strike the recording layer at the same angle.

Developers also struggle with the fact that the equipment and the discs will probably have to be proprietary, meaning that they won’t work with current technology.

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