Holographic Versatile Disc
Data Storage Technology using holography have been proposed in 1963, but until recently, its commercial implementation was impossible because of the holders do not require as much capacity, and reliability. Developments in this area deal with many firms, for example, Japan's Optware, but to date the greatest success achieved founded in December 2000 by Lucent Technologies company InPhase, which was able with the help of modern materials to realize the possibility of holography on a new technical level.
New realization of holographic technology, also known as "holographic memory", allows you to record 300 GB drive for information about ten times faster than modern recording devices on conventional DVD - claimed the writing speed reaches 160 Mbit / s! In theory, technology, to establish which InPhase announced in 2001, provides an opportunity to write to disk 1.6 terabytes of data, and the writing speed of up to 960 Mbps, but so far only method of production of spent carriers fewer and more simple equipment . According to specialists, for one disc can be to write more than 240 hours in a televised video quality, more than 18 months of radio broadcasts to 1.6 million high-resolution digital photos, or 780 million pieces of A4 paper with the text, which is comparable with the library, consisting of four million volumes.
Wheels used for holographic recording, slightly more than the diameter of traditional optical media - not their diameter is 12, and 13.3 cm, more precisely, 5.25 inches. In addition, the new drives a little thicker than normal DVD. Wheels are placed in protective plastic cartridge - recording and playback is done without extracting the holders of those cartridges.
The principle of recording holographic disc, according to InPhase Technologies, is as follows. The light laser beam is divided into two flow: signaling, which, actually, and passes useful information and reference for performing official duties. In the place where these flows intersect in recordable media, and a hologram.
Encoding data in signal stream is made using the so-called spatial light modulator (SLM), which transforms data from binary code, consisting of zeros and ones in the optical matrix of light and dark pixels, reminiscent chessboard. Data merged into arrays or order page volume million bits, the exact number is determined by modulator SLM.
The intersection of reference and signal flows formed hologram recorded in the photosensitive layer media: in the places where the projected light pixels optical matrix, the chemical reaction takes place, resulting in record holograms and implemented. By changing the angle of the reference flow, the wavelength or position of the medium in the same site photosensitive material can be written many different holograms. This method "multiplex" record made it possible to significantly increase the density recording, and, consequently, the potential capacity of the carrier. According to the developer, is currently recording density using a blue laser with a wavelength of 407 nanometers is more than 250 gigabytes per square inch.
The principle of reading the data also very simple: the reference beam, aiming at the vehicle, reflects from the hologram and reconstructed the recorded information which is projected to an array of sensors that can read data in parallel from multiple holograms. In parallel use of reading and lay a secret high-speed data transmission.
The main challenge facing developers of InPhase Technologies, a search for suitable material for data storage. Scientists from Bell Labs worked on this material for seven years, and the result of their research was the material with brand names Tapestry, featuring high photosensitivity, wide dynamic range, optical transparency, stability and spatial thermal characteristics as well as easy to manufacture. This material and used the company InPhase Technologies, isolated in their time of Bell Labs.
The disadvantage of the holders on the base polymer materials is a compression seal or limiting the amount of data that could be placed on every cubic centimeter. The submission Tapestry walked around this problem this way: this photopolymer consists of a mixture of two compatible, but regardless polymerization chemical components. Wheels are formed by natural polymerization one of the components, thus creating molecular grid serving as a supporting environment. Another, photosensitive component does not pass phase polymerization and dissolves in the lattice, making geometric stability achieved during the recording of data and durability.
InPhase and specialists have developed a special process ZeroWave, providing flat production of optical media at minimal cost, which will enable these carriers to be competitive in the mass market.
Have been solved and a number of other problems hindering the commercial use of holographic recording. In particular, was expanded working temperature range of recording layer, and in the recording and readers have been applied widespread inexpensive laser head with a red and blue laser. An array of sensors in new technology were serially produces KPOM-matrix, which are fitted with digital cameras and of high quality along with an acceptable price. In the role of spatial light modulators (SLM) played a digital micro-mirror and ferro-electric modulators used in digital TV and video. Guaranteed term storage of data on new media has been brought up to 50 years, which is comparable with conventional CD-RW, claimed the longevity of 20 to 100 years, depending on the manufacturer.
Representatives called InPhase Technologies mass merits of new technology, due to the fact that on a small disk can store such volumes of data that today can be stored on multiple hard drive expensive servers. One of the applications of holographic disks is, of course, professional videotape, because these disks allow capture, edit, store and distribute video on the same media.
Holographic technology provides a new level of copyright protection for digital content: storage of data on full-depth recording layer complicates pirated discs replication, and to verify the authenticity of the disk with the film or computer game can be used holographic "watermarks".
The first television network that broadcasts videotape provided with holographic disc, developed by InPhase Technologies, became a U.S. company Turner Network Television. October 21, 2005 engineers of both companies on the disk, made by Hitachi Maxell, advertisement of new technology. Advertising has been electronically read and transferred to the server Turner Network Television, which issued after the broadcast in a strictly scheduled time. In addition, the movie remains active and will be issued a broadcast to anyone who will seek our schedule this cable network. The first public demonstration of holographic disks in Japan was held at the International Broadcast Equipment Exhibition (InterBEE), held from 16 to 18 November in Tokyo.
Companies InPhase Technologies and Hitachi Maxell announced that the new media, as well as recording and reproducing devices already available on the market in October 2006. First, selling CDs with the possibility of a one-time record volume of 300 GB, by the end of 2007 container carriers planned to bring up to 800 gigabytes, and by 2010 - up to 1.6 terabytes. Meanwhile, all the family will be back compatible. According to the Executive Director InPhase Technologies Nelson Diaz, full backward compatibility is extremely important for data storage, and this compatibility will be maintained and the rewritable disc that must be submitted in 2007. Price first recorders, estimated to representatives of the developer, range from 12000 to 15000 U.S. dollars, but with the growth of sales and increased production drives the price could quickly fall.
Holographic discs produced by Hitachi Maxell at the Japanese factory in Tsukuba of the components supplied by the German chemical concern Bayer. The final price with the possibility of a single disc recording has not yet been determined, but estimated the representatives of Japanese firms, it will be about 120 U.S. dollars. Money, but, with each gigabytes of data storage will cost about 40 cents, for comparison, at 200 - gigabyte disk price of $ 100 per gigabyte costs 50 cents. In other words, even at the stage of pilot samples deposited gigabytes of data at the holographic disk cheaper than today's hard drive - a promising indicator.