Holographic Memory Storage

Management

Prepared BYHARISH RAMAKRISHNAN

Contents Introduction to Holographic Memory Components of Holographic Memory Basics of working Writing to disk Reading from disk Spatial Light Modulator Storing techniques Properties of Holographic Data Storage Applications of Holographic Memory Pros and Corns of the system Conclusion References

Introduction to Holographic Memory

Holographic memory is a developing technology that has promised to revolutionize the storage systems.

Holographic memory is an advanced optical storage device that can store information in the form of holographic image.

A method of producing a three-dimensional image of an object by recording on a photographic plate or film the pattern of interference formed by a split laser beam and then illuminating the pattern either with a laser or with ordinary light.

HVD technology 1. Green writing/reading laser (532

nm)

2. Red positioning/addressing laser (650 nm)

3. Hologram (data)

4. Polycarbon layer

5. Photo polymeric layer (data-containing layer)

6. Distance layers

7. Dichroic layer (reflecting green light)

8. Aluminum reflective layer (reflecting red light)

9. Transparent base

Cont..

• Holographic Versatile Disc(HVD) is an optical disk technology still in research stage which would hold up to 3.9 TB of information

• The HVD also has a transfer rate of 1 gigabyte/s

• It is a technique that can store information inside crystals or photopolymers.

Components of Holographic Memory

1. Blue-green Argon Laser2. Beam splitters to spilt the laser beam3. Mirrors to direct the laser beams4. LCD panel (spatial light modulator) 5. Lenses to focus the laser beams 6. Lithium-niobate crystal or photopolymer 7. Charge coupled device camera

Writing to Disk

working principle

SLM

Objective Lens

Cover Layer

Recording LayerReflective Layer

Inner :InformationOuter :Reference

Fourier transformedinformation beam

Diffracted referencebeam (modulated)

Diffracted informationbeam (page data)

Fourier transformedreference beam

Recorded Hologram

A Spatial Light Modulator is used for creating binary information out of laser light. The SLM is a 2D plane, consisting of pixels which can be turned on and off to create binary 1’s and 0’s.

An SLM can usually be refreshed at rates of about 1000 frames per second

SLM

Storing TechniquesMultiplexing

Angular Multiplexing : By modifying the angle of a source beam, large amount of data is stored in the volume.

Cont..

Wavelength Multiplexing : Alters the wavelength of source and reference beams between recordings

Spatial Multiplexing : Changing the point of entry of source and reference beams into the recording medium

Reading from Disk

Technology Comparison

Holographic Data Security

Data Transfer Rate

1985 1990 1995 2000 2005 2010 2015

Availability Year

1M

10M

100M

1G

10G

100GD

ata

Tran

sfer

Rat

e, b

its/s

ec

Blu-ray HD DVD

0.1M

DVD

Tape

HDD

How HVD compares with other storage device?

• While HVD is attempting to revolutionize data storage, other discs are trying to improve upon current systems. Two such discs are Blu-ray

and HD-DVD, deemed the next-generation of digital storage.

  HD-DVD Blu-ray HVD

Initial cost for recordable disc

Approx. $10 Approx. $18 Approx. $120

Initial storage capacity

30 GB 54 GB 300 GB

Applications of Holographic Memory

• Data Mining : Retrieval of data is very fast and storing large amount of data in a single disk.

• Petaflop computation : performs thousand trillion floating point operations per second.

• Holographic memory can be used as an extended DRAM with 10ns access time.

Advantages of Holographic Memory1. Resistance to damage - If some parts of the medium are damaged,

all information can still be obtained from other parts.

2. Efficient retrieval - All information can be retrieved from any part of the medium.

3. High storage capacity of 3.9 terabyte(TB)

4. While reading data the entire page of data can be retrieved quickly and at one time .

5. Backward compatible, supports CD’s and DVD’s also.

Disadvantages of Holographic Memory

• Manufacturing cost of HDSS is very high. • There is a lack of availability of resources which are needed

to produce HDSS.

• Writes in the same fashion can degrade previous writes in the same region of the medium.

Cont..

• The re-illuminated reference beam used to retrieve the recorded information, also excites the donor electrons and disturbs the equilibrium of the space charge field in a manner that produces a gradual erasure of the recording.

• The crystal used as the photographic filament must have exact optical characteristics.

Holographic Memory Systems

Fuji Photo Film Imation Toshiba Konica-Minolta Matsushita/Panasonic Memory-Tech Micron Mitsubishi Chemical Nippon Paint OPTWARE

TV Asahi Corporation TV Tokyo Corporation Warner Bros. Disney Universal Pioneer Sanyo JVC NEC InPhase Technologies Maxell Aprilis

SOME OF THE CURRENT PLAYERS

Conclusion

HVD will soon replace present DVDs.

It is currently supported by more than 170 of the world's leading consumer electronics, personal computer, recording media, video game and music companies.

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