1. Dvd(30gb) Bd(50gb)

2. It is an advanced optical disc thats presently in the development stage. The Holography technique was invented in 1948 by the Hungarian Dennis Gabor. Developed by the Holography Storage Development Forum. Storage capacity : It can store up to 1-4 TB of information in a sugar cube sized crystal. Holographic versatile disc is a holographic storage format that looks like a DVD but is capable of storing far more data. 3. It can store up to 830 times the data of a regular DVD and 160 times that of a Blu-ray disc. An HVD is a successor to todays Blu-ray and HD-DVD technologies. Data transfer rate :- 1 Gigabit per second. 4. As computer systems continue to become faster and faster, they will need a way to access larger amounts of data in shorter periods of time. This huge requirement of memory could not be available using 1st,2nd or 3rd gen. optical discs.Hence ,to full-fill these requirements HVD has become todays need. For Internet applications alone, industry estimates are that storage needs are doubling every 100 days. By the year 2010, a storage system serving an average LAN will need 100 TB and a WAN server will require 10TB to 1 petabyte of storage. 5. It is a memory that can store information in form of holographic 3D image. In it , information can be stored at high density inside crystals . Conventional memories use only the surface to store the data. But holographic data storage systems use the volume to store data. It has more advantages than conventional storage systems. Unlike magnetic storage mechanisms which store data on their surfaces, holographic memories store information throughout their whole volume. 6. In collinear holography there are two type of laser beam. 1.Red laser(Reference beam)(635nm) 2.Green laser(Signal beam)(532nm) This two beams are collimated in a single beam. The green laser reads data encoded as laser interference fringes from holographic layer near the top of the disc. 7. Hologram The recorded patterns of light rays after interference are called a hologram. Microscopic Photo of Stored Hologram 8. Holographic storage systems contain some components basic to the setup. These are :- a) Laser Beam b) Beam Splitters to split the Laser Beam c) Mirrors to direct the Laser Beam d) Spatial Light Modulator(SLM) e) Lenses to focus the Laser Beam f) Recording Material or Photopolymer i.e.(Lithiumniobate Crystal) g) CCD cameras 9. In a holographic memory device, a laser beam is split in two, and the two resulting beams interact in a crystal medium to store a holographic recreation of a page of data. 10. Translates electronic data (0's and 1's) into optical pattern of light and dark pixels. Data is arranged in an array similar to a checkerboard of usually 1M (million) bits. By varying the angle of the reference beam, wavelength many holograms can be stored in the same volume of storage material. SPATIAL LIGHT MODULATOR (SLM) 11. Writing Data The process of writing information onto an HVD begins with encoding the information into binary data to be stored in the SLM. These data are turned into ones and zeroes represented as opaque or translucent areas on a "page" -- this page is the image that the signal beam is going to pass through. WORKING OF HVD 12. 1. Once the page of data is created, the next step is to fire a laser beam into a beam splitter to produce two identical beams. One of the beams is directed away from the SLM -- this beam becomes the reference beam. The other beam is directed toward the SLM and becomes the signal beam. 2. When the signal beam passes through the SLM, portions of the light are blocked by the opaque areas of the page, and portions pass through the translucent areas. In this way, the signal beam carries the image once it passes through the SLM. 3. When the reference beam and the signal beam rejoin on the same axis, they create a pattern of light interference -- the holography data. This joint beam carries the interference pattern to the photopolymer disc and stores it there as a hologram. 13. In order to retrieve and reconstruct the holographic page of data stored in the crystal, the reference beam is shined into the crystal at exactly the same angle at which it entered to store that page of data. Each page of data is stored in a different area of the crystal, based on the angle at which the reference beam strikes it. During reconstruction, the beam will be diffracted by the crystal to allow the recreation of the original page that was stored. Reading Data 14. To read the page ,one need to pass it through detector and then through CCD camera, which will project the data on to the display panel. The key component of any holographic data storage system is the angle at which the second reference beam is fired at the crystal to retrieve a page of data. It must match the original reference beam angle exactly. A difference of just a thousandth of a millimeter will result in failure to retrieve that page of data. 15. Disc Diamet er Laser wavelength Capacity Writing/ Reading Speed Discs Approx. Cost Recordabl e Player Approx. Cost Holographic Versatile Discs (HDSS) 120 532 nm (green) 300 GB 1-4 TB 1 GB/s $120 $3000 Blu-ray Discs 120 405 nm (blue) 25 GB 50 GB 36.5 Mb/s $18 $2000 Digital Versatile Discs 120 650 nm (red) 5 GB 30 GB 36.5 Mb/s $10 $2000 Compact Discs 120 780nm (infrared) 783 MB 1.3GB 36.5 Mb/s $4 $200 16. It has been estimated that the books in the U.S. Library of Congress, the largest library in the world , could be stored on six HVDs. The pictures of every landmass on Earth - like the ones shown in Google Earth - can be stored on two HVDs. With MPEG4 ASP encoding, a HVD can hold anywhere between 4,600-11,900 hours of video, which is enough for non-stop playing for a year. 17. Efficient Retrieval Large Capacity:1 HVD=6000 cd=830 DVD=160 BD High Data Transfer Rate Fault and Damage Tolerance Reads and Writes quickly Resistant to Damage 18. Disadvantages It is very difficult to arrange all of those components like CCD camera , SLM and beam steering devices. Needs good recordings sensitive material to allow high data transfer rate. If too many pages are stored in one crystal, the strength of each hologram gets diminished. Manufacturing cost HVD is very high and there is a lack of availability of resources which are needed to produce HVD. You would be unable to locate the data if theres an error of even a thousandth of an inch. Initial price of the player and disc are high. 19. Future Aspects Have tremendous implications in the commercial, industrial and d-Cinema. We will find wide use for backing up and archiving the media libraries, including the one at the Hollywood studios. 20. The fourth-generation optical disc that would replace the Blu-ray Disc format will be of terabyte-class capacity. Prof. Inoues research group successfully put a Holographic Versatile Disc (HVD) based on the collinear holography technique into practical use. The HVD format is expected to be able to hold over 1.3 terabytes of information on a CD-size disc in the future. ReseaRch OveRview 21. Group of some 20 major electronics manufacturers jointly move for standardization of this format. HVD was adopted for international standard by Europe-based Ecma international in 2007, raising expectations for its domination of international markets. The Research Center for Advanced Photonic Information Memories was established on the campus of Toyohashi University of Technology, and joint development is underway through an academic- industrial consortium that uses the center as a base. The global market is expected to exceed that of the Blu-ray Disc (Estimated to be about 300 billion yen in Impact of Research Achievements 22. Conclusion The future of holographic memory is very promising. The holographic storage provide high data density. It can easily store 1000GB of data in a small cubic centimeter crystal reducing the cost on the other hand. It may offer high data transfer rate. But even then the holographic way of storing data is still at the base stage and it may take another couple of years for this technique to hit desktop with a real life data storage solution. However this technology itself is dazzling and aims to light up the desktop Experiences.