August 1, 2003 Georgia Institute of Technology
The The NNational ational AAeronautics and eronautics and SSpace pace AAdministration's dministration's SSummer ummer HHigh School igh School AApprenticeship pprenticeship RResearch esearch PProgramrogram
By: Angel CarrasquilloBy: Angel Carrasquillo
Michael HuynhMichael Huynh
Holographic Data StorageHolographic Data Storage
OutlineOutline
IntroductionIntroduction
What is What is Holographic Data Holographic Data Storage?Storage?
How does it work?How does it work?
The SystemThe System
The Storage The Storage MediumMedium
Recording a Recording a HologramHologram
Uses of the SystemUses of the System
Pros and ConsPros and Cons
Experimental Experimental ResultsResults
ConclusionConclusion
A hologram is a 3D image reproduced A hologram is a 3D image reproduced form a pattern of interference.form a pattern of interference.The Holography technique was invented The Holography technique was invented in 1948 by the Hungarian Dennis Gaborin 1948 by the Hungarian Dennis GaborThis technique have been evolving in This technique have been evolving in the last few years.the last few years.It promises to be the data storing system It promises to be the data storing system of the future.of the future.
IntroductionIntroduction
Storage system in which two beams Storage system in which two beams from the same laser source are used to from the same laser source are used to record data into a recording medium.record data into a recording medium.
Stores information in the entire volume Stores information in the entire volume of the recording medium.of the recording medium.
System that can store up to 1 terabyte System that can store up to 1 terabyte of data into a 1 cmof data into a 1 cm33 recording medium. recording medium.
What is HolographicWhat is HolographicData Storage?Data Storage?
How does it work?How does it work?
Two beams come to Two beams come to the crystal and meet the crystal and meet at a specific angle.at a specific angle.
The beams create an The beams create an interference pattern interference pattern inside the crystal.inside the crystal.
The pattern is The pattern is recorded inside the recorded inside the crystal.crystal.
How does it work?How does it work?
For read-out only the reference beam and the For read-out only the reference beam and the crystal are needed.crystal are needed.
Reference beam should Reference beam should be at the same angle it be at the same angle it was when recorded.was when recorded.
Reference meets with Reference meets with the interference pattern inside the crystal and the interference pattern inside the crystal and the signal beam is recreated.the signal beam is recreated.
The SystemThe System
Basic components of the System:Basic components of the System:
– LaserLaser
– Recording Recording MediumMedium
– MirrorsMirrors
– Spatial light Spatial light modulatormodulator
– Beam splitterBeam splitter
– ShuttersShutters
– IrisIris
– LensesLenses
– Half-wave plateHalf-wave plate
The SystemThe System
Every single component had to be perfectly aligned.Every single component had to be perfectly aligned.
Recording a HologramRecording a Hologram
Laser beam alignmentLaser beam alignment
Plane wave obtained Plane wave obtained through spatial filter and through spatial filter and lens.lens.
Beam splitter.Beam splitter.
Signal beam to SLMSignal beam to SLM
Reference beam remains Reference beam remains a plane wave.a plane wave.
CCD used for detection of CCD used for detection of reconstructed hologram.reconstructed hologram.
The Recording MediumThe Recording Medium
Photorefractive and Photorefractive and Photopolymer Crystals.Photopolymer Crystals.
Media parameters: Media parameters: – Diffraction efficiencyDiffraction efficiency– Holographic fidelityHolographic fidelity– SensitivitySensitivity– Dynamic rangeDynamic range– Volatility. Volatility.
The Recording MediumThe Recording Medium
Photorefractive Crystal: Lithium Photorefractive Crystal: Lithium Niobate (LiNbONiobate (LiNbO33). Usually doped ). Usually doped with elements such as: iron, with elements such as: iron, manganese, or chromium.manganese, or chromium.When the crystal is doped, levels When the crystal is doped, levels are created where electrons reside.are created where electrons reside.Interference pattern excites Interference pattern excites electrons to the Conduction Band.electrons to the Conduction Band.Electro-optic effect.Electro-optic effect.Refractive index changes.Refractive index changes.
CB
VB
Fe 3+Fe 2+
hν
Can be used to store any kind of Can be used to store any kind of information from documents to videos.information from documents to videos.
Will be useful for:Will be useful for:– GovernmentsGovernments– LibrariesLibraries– BusinessesBusinesses– PeoplePeople
Uses of the SystemUses of the System
Pros and ConsPros and Cons
Pros:Pros:– Storage capacityStorage capacity
High DensityHigh DensitySmall VolumeSmall Volume
– EffectiveEffectiveRapid Data RateRapid Data RateFast Access Fast Access TimesTimes
– Swift searchingSwift searching
Cons:Cons:– SensitiveSensitive– Material Material
LimitationsLimitations– NoiseNoise– CostCost
Our setup consisted of:Our setup consisted of:
-Laser -Laser -Iris-Iris
-Half-waveplate-Half-waveplate -Beam splitter-Beam splitter
-Spatial light modulator-Spatial light modulator-Reflecting mirror-Reflecting mirror
-Focal lens 90 mm-Focal lens 90 mm -Power detector-Power detector
The SetupThe Setup
SF
Crystal (LiNbO3: Fe)
FL90 Irisλ2
BS λ2
Laser
DET
Experimental ResultsExperimental Results
NoiseNoise
Caused by:Caused by:– TemperatureTemperature– Loud SoundsLoud Sounds– MovementMovement– LightLight
Experimental ResultsExperimental Results
Holographic Data Storage is a convenient Holographic Data Storage is a convenient and effective way of data storage.and effective way of data storage.
ConclusionConclusion
