Z-holographic Versatile Disc
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Transcript of Z-holographic Versatile Disc
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( HVD )
HOLOGRAPHIC VERSATILE DISC
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CONTENTS
1. INTRODUCTION
2. UNDERLYING TECHNOLOGY-
HOLOGRAPHY
3. RECORDING DATA
4. READING DATA
5. HVD- STRUCTURE
6. COMPARISON
7. TYPES : WORM & RW8. REFERENCES
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INTRODUCTION
Next-Next Generation Technology
Scientist J. V. Heerden came up with this idea in 1960
Media type : Ultra-high density optical disc
Encoding : MPEG-2, MPEG-4 AVC (H.264), and VC-1 Capacity theoretically up to 3.9 TB
Developed by HSD Forum
Usage :Data storage,
:High-definition video & the possibility of ultra high
definition video
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FEATURES
Data transfer rate : 1gbps.
The technology permits over 10 kilobits of data to be written and
read in parallel with a single flash.
Most optical storage devices, such as a standard CD saves one bit
per pulse. HVDs manage to store 60,000 bits per pulse in the same
place.
1 HVD = 5800 CDs = 830 DVD =160 BLU-RAY
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HOLOGRAPHY VS PHOTOGRAPHY
Black and white photograph
Contains Intensity distribution
Color photograph Intensity and wavelength
Hologram
Intensity, phase, and sometimes wavelength
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HOLOGRAPHY
INVENTED BY
SCIENTIST
GABOR IN 1947.
CONTAINS
INFORMATION
ABOUT AMPLITUDE
AND PHASE OF
OBJECT WAVE.
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RECORDING DATA
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SPATIAL LIGHT MODULATOR (SLM)
Translates electronic data (0's and 1's) into
optical pattern of light and dark pixels.
Data is arranged in an array similar to acheckerboard of usually 1M (million) bits.
By varying the angle of the reference
beam,wavelength or media position, manyholograms can be stored in the same
volume of storage material.
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READING DATA
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HVD TECHNOLOGY
HVD uses a technology called 'collinear holography,'
Two laser rays, one blue-green and one red are used.
The role of the blue-green laser is to read the data encoded in theform of laser interference fringes from the holographic layer.
The red laser serves the purpose of a reference beam and also toread the servo info from the aluminum layer.
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HVD STRUCTURE
1. Green writing/reading laser (532 nm)
2. Red positioning/addressing laser (650
nm)
3. Hologram (data)
4. Polycarbon layer
5. Photopolymeric layer (data-containing
layer)
6. Distance layers
7. Dichroic layer (reflecting green light)
8. Aluminium reflective layer (reflecting
red light)9. Transparent base
P. PIT
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COMPARISON
Parameters DVD BLU-RAY HVDcapacity 4.7 GB 25 GB 3.9 TB
Laser wave length 650 nm
(red)
405 nm
(blue)
532 nm(green)
Disc diameter 120 mm 120 mm 120 mm
Hard coating no yes yes
Data transfer rate(raw data)
11.08mbps
36 mbps 1 gbps
Data transfer rate(audio/video)
10.08mbps
54 mbps 1 gbps
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supports some irreversiblephotochemical reaction
triggered by the bright
regions of the optical
interference pattern
material diffuses from darker to
brighter regions so that short
monomer chains can bind together
to form long molecular chains
READ ONLY HVD
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READ/WRITE HVD
Uses inorganic photorefractive crystals.
Electrons get photo-excited at the
bright fringes diffuse or drift and
are re-trapped at a dark fringe.
Trapped charge can be rearranged
by later illumination, so it is possible
to erase recorded holograms.
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INTERESTING FACTS
It has been estimated that the books in the U.S. Library ofCongress, the largest library in the world , could be stored on
six HVDs.
The pictures of every landmass on Earth - like the ones shown inGoogle Earth - can be stored on two HVDs.
With MPEG4 ASP encoding, a HVD can hold anywhere between4,600-11,900 hours of video, which is enough for non-stopplaying for a year.
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COMPONENTS NEEDED FOR HVD READER
A blue-green argon laser
Beam splitters to spilt the laser beams
Mirrors to direct the laser beams
LCD panels (spatial light modulator) Lenses to focus the laser beams
Lithium-niobate crystals or photopolymers and
Charge-coupled device (CCD) cameras.
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PROTOTYPE PHOTO
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REFERENCES
Psaltis, D. Mok, F. Holographic memories. Scientific American
Encyclopedia of Optical Engineering