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HOLOGRAPHY MEMORYBY –BHAVITH.D

5TH SEM S.D.M.T.IReg.No:497IS08003

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Capacity:700 mb Capacity: 30-50GbCapacity:1-4TBCapacity:4.7Gb

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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).

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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.

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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.

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COMPONENTSMost 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

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To spilt the laser beam

To direct the laser beams

spatial light modulator

photopolymer

Interprets the digital

informationBlue-green argon laser

Beam splitters

Mirrors

LCD panel

Lithium-niobate crystal

CCD camera

Basic Components

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Holographic Versatile Disc structure1. Green writing/reading

laser (532 nm) 2. Red

positioning/addressing laser (650 nm)

3. Hologram (data)4. Polycarbon layer5. Photo polymeric layer

(data- containing layer)6. Distance layers7. Dichroic layer (reflecting

green light)8. Aluminum reflective

layer(reflecting red light)

9. Transparent base

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METHOD OF STORING DATAWhen 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.

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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

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METHOD OF RETRIVING DATATo 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.

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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.

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ADVANTAGES

Large Data Density.

Better Reliability.

Large Capacity.

High Data Transfer Rate.

Fault and Damage Tolerance.

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LIMITATIONS AND CHALLENGESIt 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.

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APPLICATIONS

A) Petaflop Computing

B) Data Mining

C) Future Computing System

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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.

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THANK YOU