HOLOGRAPHIC DATA STORAGE:
© 2007 by Holovisions.com
Holographic data storage and retrieval involves – (1) translating (electronic) data into light patterns that are encoded within a laser beam, (2) creating and imprinting a hologram (holographic interference pattern) of the laser beam with the data and a second beam within three-dimensional photosensitive media, (3) recreating the hologram at a later time, and then (4) retranslating the hologram back into the original (electronic) data. The laser beam containing the data (called the signal beam) and the second beam (called the reference beam) generally come from a single original laser beam that is split in two with a mirror. The signal beam is sent through a Spatial Might Modulator (SPM) which encodes it with data.
Holographic data storage systems can access data much quicker than conventional methods. A single hologram, sometimes called a “page”, can contain a megabyte of data. Since holographic data storage stores and retrieves an entire page of data at a time, holographic data storage and retrieval can be much quicker than conventional, bit-by-bit data storage and retrieval methods.
Since holographic data storage systems store data throughout the depth of three-dimensional media, not just on the media surface, they can store a large amount of data in a relatively small space. Thousands of holographic pages can be stored on a single holographic disk. Since holographic media do not have to be spun to be read, this opens up greater flexibility for media size and shape. Although first-generation holographic data storage media are disks, future storage media can be cubes or other shapes. For example, a holocube the size of a sugar cube should be able to store a terabyte or more of information.
In addition to access speed and storage density advantages, holographic storage media are expected to maintain data integrity for up to 50 years. This gives holographic storage a durability advantage over magnetic tape for long-term data archiving.
The first commercial holodisks are being launched in 2007. The first holodisks, Tapestry by InPhase Technologies, have a 300 gigabyte capacity and are currently read only (HoloROM). They are relatively expensive and expected to be primarily used for high-definition digital video broadcasting and movie distribution for digital theaters. However, their cost is expected to decrease over time, even as their storage capacity and access speeds are expected to increase. This should resulting in expanded useage. InPhase’s holodisks are supported by Maxwell, Hitachi, Sony, Sanyo, HP, IBM, Toshiba, Samsung, and Matsushita.
Other companies are also working on holographic data storage. Optware Corporation is developing their holographic versatile disk using collinear holography -- in which the signal and reference beams are on the same axis. Optware has received support from Fuji, CMC Magnetics, Alps Electric, CMC Magnetics, EMTEC (MPO International), Konica Milota, Mitsubishi, and Pulstec Industrial. Optware also has petitioned the ECMA to become the standard format. However, Opware’s product has been delayed. Access Optical Networks is working on a holographic storage system that is entirely optical. They hope to avoid having to convert data from electronic to holographic form, and vice versa.
© 2007 by Holovisions.com™