Holography memory is an advanced optical storage device that can store large amounts of data as holographic images. It uses interference patterns of laser light to store digital data pages in a crystal at high density, potentially storing terabytes of data in a sugar cube sized space. While holographic storage promises extremely high capacity and reliability, there remain technical challenges in arranging all the necessary components like cameras and light modulators. The technology is still in development but could transform data storage if the challenges can be addressed.

1. HOLOGRAPHY MEMORY BY –BHAVITH.D 5TH SEM S.D.M.T.I Reg.No:497IS08003 1

2. Capacity:4.7Gb Capacity:700 mb Capacity:30-50Gb Capacity:1-4TB 2

3. INTRODUCTION Holography memory is an advanced optical storage device that can store information in the form of holographic image. It can store up to 1-4 TB of information in a sugar cube sized crystal. Holography data storage is a volumetric approach of storing data(use the volume of recording medium). 3

4. WHY WE NEED THIS //////?? “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. 4

5. CONCEPT Holography the wave field of light(i.e the object and reference wave) scattered by an object is recorded on a place (i.e. holographic material) as an interference pattern. 5

6. COMPONENTS Most 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) A liquid crystal Display panel(SLM) e) Lenses to focus the Laser Beam f) Recording Material g) CCD cameras 6

7. Basic Components spatial light modulator LCD panel To direct the laser beams photopolymer Lithium-niobate crystal Mirrors Beam splitters CCD camera To spilt the laser beam Interprets the digital information Blue-green argon laser 7

8. Holographic Versatile Disc structure Green writing/reading laser (532 nm) Red positioning/addressing laser (650 nm) Hologram (data) Polycarbon layer Photo polymeric layer (data- containing layer) Distance layers Dichroic layer (reflecting green light) Aluminum reflective layer(reflecting red light) Transparent base 8

9. METHOD OF STORING DATA When the blue-argon laser is focused ,a beam splitter splits it into two beams a reference beam and a signal beam . The signal beam will go straight bounces off one mirror & travel through a SLM. The signal beam passes through a SLM where digital information, organized in a page like format of ones and zeroes, is modulated onto the signal beam as a two dimensional pattern of brightness and darkness . The information from the page of binary code is carried by the signal beam around to the light sesitive Lithium Niobate crystal. 9

10. A second beam called reference beam shoots out the side of the beam splitter and takes a separate path to the crystal. When the two beams meet, the interference pattern that is created stores the data that is carried by the signal beam on to the surface of the holographic material as a hologram.(Data is stored as a hologram) Different data pages are recorded over the surface depending on the angle at which the reference beam meets the signal beam 10

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13. METHOD OF RETRIVING DATA To retrieve data, the reference beam is focused on the hologram at a particular angle ; this will retrieve the modulated data stored at the same angle of interference . 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. 13

14. 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. 14

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16. ADVANTAGES Large Data Density. Better Reliability. Large Capacity. High Data Transfer Rate. Fault and Damage Tolerance. 16

17. LIMITATIONS AND CHALLENGES It is very difficult to arrange all of those components like CCD camera , SLM arrays 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. 17

18. APPLICATIONS A) Petaflop Computing B) Data Mining C) Future Computing System 18

19. 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 Experienences. 19

20. THANK YOU 20