Holographic Storage

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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 Hologram
• Can be used to store data
• Uses coherent light
• Reflection Hologram
• The kind you find on credit cards
• Uses 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
Reflection
Reference beam
Stored in film
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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
EConduction
External electric field
EValence
Object Image
Reference Beam
Object Image
Reference Beam
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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 cents
• DVDDL 8.4 Gbytes - 3
• Blu-Ray DL 50 Gbyte - 30
• InPhase Tapestry 300 Gbyte - 250
• Hard disk 1 Tbyte - 300
• HVD (future) 4 Tbytes

• Transfer rates
• CD-ROM 52x 5 Mbit/second
• DVD 16x 20 Mbit/s
• InPhase Tapestry 20 Mbit/sec
• Blu-Ray and HDDVD 30 Mbit/sec
• 7200 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?KEYPSISDGVolum
  e6252Issue1
• 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.ht
  m
• http//en.wikipedia.org/wiki/Holography
• http//en.wikipedia.org/wiki/Holographic_Versatile
  _Disc
• http//www.inphasetechnologies.com/downloads/pdf/p
  roducts/2007TapestryProductBrochure.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.gi
  f

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Questions?