Holographic Storage

Physics 496

Michael Atkinson

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Why Holographic Storage?

Storage Density media stores data in whole volume

Speed parses many bits at once

Reliability Good shelf life High number of write cycles

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Outline

Holography Concepts

Refractive index modulation

Storing data

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Types of Holograms

Transmission HologramCan be used to store dataUses coherent light

Reflection HologramThe kind you find on credit cardsUses white light

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Holography vs Photography

Black and white photograph Intensity

Color photograph Intensity and wavelength

Hologram Intensity, phase, and sometimes wavelength

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Review of Interference

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Creating Hologram

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Pattern Left on Media

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Reconstructing the Image

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Qualitative Explanation of Storage

Reference beam Object image Resultant pattern Stored in film

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Qualitative Explanation of Reconstruction

Reference beam Stored in film Reflection

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Photorefractive effect

Electrons gain energy from light

Leave Valence band, can move freely

Diffuse toward dark areas

When beams removed, electrons settle and we have internal net electric fields

Index of refraction changed due to electro-optic effect

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Intensity Threshold

EValence

EConduction

Object Image

Reference Beam

Object Image

Reference Beam

External electric field

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Storing Data

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Reading Data

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Current State of Technology

Storage CD-ROM: 800 Mbytes – 10 centsDVD+DL: 8.4 Gbytes - $3Blu-Ray DL: 50 Gbyte - $30InPhase Tapestry: 300 Gbyte - $250Hard disk: 1 Tbyte - $300HVD (future): 4 Tbytes

Transfer ratesCD-ROM 52x: ~ 5 Mbit/second DVD 16x: ~ 20 Mbit/sInPhase Tapestry: 20 Mbit/secBlu-Ray and HDDVD: ~ 30 Mbit/sec7200 rpm Hard disk: 80 Mbit/sec

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References Physics for Scientists and Engineers with Modern Physics – Vol 2, Serway and Jewett

International Conference on Holography, Optical Recording, and Processing of Information: http://spiedl.aip.org/dbt/dbt.jsp?KEY=PSISDG&Volume=6252&Issue=1

Thermally sensitized optical recording in azobenzene polymers• D.Illieva, M. Ivanon, T. Petrova, V. Dragostinova, G. Minchev, T. Todorov, L.

Nikolova Refractive data of optical plastics for laser applications

• N. Sultanova, S. Kasarova, C. Ivanov, I. Nikolov Pulse Recording Dynamics of Diffraction Gratings in Xanthene Dyes Sensitized

Photopolymer Material• E. Vasilyev, V. Shelkovnikov, E. Pen, A. Plechanov

Holographic recording in nanoparticle-doped photopolymer• I. Naydenov, H. Sheriff, S. Mintova, S. Toala

http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/holcon.html http://www.research.ibm.com/journal/rd/443/ashley.html http://www.howstuffworks.com/holographic-memory.htm http://en.wikipedia.org/wiki/Holography http://en.wikipedia.org/wiki/Holographic_Versatile_Disc http://www.inphasetechnologies.com/downloads/pdf/products/2007TapestryProductBrochur

e.pdf

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Image Sources

Slide 2: ad from slashdot.com Slide 6:

http://sol.sci.uop.edu/~jfalward/lightinterference/lightwaveshowingelecvector.jpg http://www.chem.wisc.edu/~newtrad/CurrRef/BDGTopic/BDGFigs/3_13cdfere.gif

Slide 7: http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/imgopm/holo2.gif

Slide 8: http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/modpic/holripp.jpg

Slide 9: http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/imgopm/holo3.gif http://www.research.ibm.com/journal/rd/443/ashle2.gif

Slide 10: drawn by me

Slide 11: drawn by me

Slide 13: taken from Thermally sensitized optical recording in azobenzene polymers, D.Illieva, M. Ivanon, T. Petrova, V.

Dragostinova, G. Minchev, T. Todorov, L. Nikolova Slide 14:

http://static.howstuffworks.com/gif/holo-memory.gif Slide 15:

http://static.howstuffworks.com/gif/holo-memory2.gif Slide 16:

http://www.inphase-technologies.com/images/products/drive-media_lg.jpg Slide 19:

http://physicsweb.org/objects/world/13/7/7/pw-13-07-07fig4.gif

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Questions?