It is a memory that can store information in form of holographic image.It is a technique that can store information at high density inside crystals or photopolymers.It provides data to be written beneath the surface of the disc.Holographic memory can store up to 1 Tb in a storage medium the size of a sugar cube crystal.

1. Seminar Report on
HOLOGRAPHIC MEMORY

2. What is Holographic Memory ?
• It is a memory that can store information
in form of holographic image.
• It is a technique that can store
information at high density inside crystals
or photopolymers.
• It provides data to be written beneath the
surface of the disc.
• Holographic memory can store up to 1
Tb in a storage medium the size of a
sugar cube crystal.

3. 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

4. Working Principle

5. Continues..

6. Creating Holograms

7. Reconstructing the image

8. Shift Characteristics
Shift multiplexing
read/write can be
done at 3μpitch
Read-out
Page DataShift:
1μm pitch
Y
X
2μm
3μm
1μm

9. Properties of Hologram
• A block or sheet of photosensitive material which
records the diffraction of two light sources.
• A laser beam is splitted into two beams:
 Source beam
 Reference beam
• The two beams diffracts to form the image on the
recording medium.

10. Spatial light modulator
• It is used for creating binary information out of
laser light.
• It is a 2D plane, consisting of pixels which can be
turned on and off to create binary 1.s and 0.s.
• It contains a two-dimensional array of windows,
which are only microns wide.

11. Page Data Access
• As the data is stored in the form of holograms,
data retrieval must be in the same form.
• So, a holographic system sends data in the form
of pages.
• It provides fast access times.

12. Error Correction
• As the density of data is massive, it is prone to
errors.
• Errors can be controlled by:
o Recording errors
o Page level parity bits
o Interfacing

13. Recording Errors
• Cause: Noise generated by laser beam
• Result: Can change a binary 0 to binary 1
• Possible Solution: Improvement in laser beam
and recording material

14. Page-level Parity Bits
• Data is stored in the form of 2-D array
• Odd no. of bits accounts for parity 1
• Even no. of bits accounts for parity 0
• Parity check bits are used
to identify any errors present
in the array

15. APPLICATIONS OF HOLOGRAPHY
• Product packaging
• Data mining
• Holograms are used in credit card, license,
books, magazine.
• Used in airplanes etc. in heads up display
• Used in testing for fractures and quality control.
• Application in future computer system.
• Used in 3-D projection of artistic images or
expressions.

16. CONCLUSION
There is bright scope of advancement in the field of
holography. 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.
Till, the holographic storage is at the beginning
stage, it will mark its existence soon in the market.

17. References
• www.almaden.com
• www.eik.bme.hu
• www.vision.caltech.edu
• Mansi, Mark “the hard disk survival guide” ,
BPB publications , 1993

18. QUERIES??