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Guys this is a very basic presentation of holo mem sys.For now this subject is still under observation.
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Future Technology
What is Holography
Holography is a technique which enables three-
dimensional images to be made. It involves the
use of a laser, interference, diffraction,
light intensity recording and suitable illumination
of the recording.
The image changes as the position and
orientation of the viewing system changes in
exactly the same way as if the object were still
present, thus making the image appear three-
dimensional.
Who invented holography?
Dennis Gabor was
a Hungarian-British electrical
engineer and physicist, most
notable for
inventing holography, for which
he later received the
1971 Nobel Prize in Physics
Three dimensional or “holographic” data
storage involves using the entire media
for storage, not just a few layers like we
currently use today.
The process is accomplished by using
two laser beams, instead of one, to
write data to the disk.
1. The object is converted into binary
code of 1’s and 0’s like we use today.
2. Next, the 1’s and 0’s are converted
into a matrix of light and dark squares.
3. Those light and dark squares are then
electronically sent to a spatial light
modulator (SLM).
4. The laser beam then shines through
the spatial light modulator (SLM).
5. Pixels of the spatial light modulator
filter (block or allow) the light thus
encoding the data into the laser beam.
SLM
Objective Lens
Cover Layer
Recording Layer
Reflective Layer
Inner: Information
Outer: Reference
Diffracted information
beam (page data)
Diffracted reference
beam (modulated)
Recorded Hologram
A green and red laser beam
are collimated in a single beam.
The green laser reads data encoded
as laser interference fringes from
a holographic layer near the top of
the disc.
A red laser is used as the reference
beam to read servoinformation from
a regular CD-style aluminium layer
near the bottom.
Red - 650 nm
Green – 532 nm
Many disk prototypes
have been looked at over
the years, however, the
industry standard has
now accepted having
the HVD disk include a
reflective layer in order to
be backward compatible
and to assist with
tracking of the write
beam. Di-isobutylacrylamide
(DBA)
A simplified HVD system
consists of the following main
components:
•Blue or green laser (532-nm
wavelength in the test system)
•Beam splitter/merger
•Mirrors
•Spatial light modulator (SLM)
•CMOS sensor
•Photopolymer recording medium
Recording Process
Media
Lens
SLM
Information Pattern
Reference
Pattern
Reconstruction Process
Media
Reconstructed
SLM
Beam SplitterLens
Reference
Pattern
Reflective
Layer
Increased storage capacity
Increased read/write speed
Longer storage life
Security
In today’s world, digital media is becoming
more and more common and is requiring
more storage to meet the new demands.
More industries are now using digital
storage than ever before.
200 DVD’s can fit on one 1 TB holographic
disk with a future capacity of 6 terabytes.
IBM's test platforms can store up to 390
bits per square micron (a micron is a
millionth of a metre). DVDs, by contrast,
have a storage density of about five bits
per square micron.
DVD DVD Blu-Ray Blu-Ray HVD
Number of Layers Single Dual Single Dual 200+/-
Recording Capacity 4.7GB 9.4GB 25GB 50GB 1TB
Data Transfer Rate 11.08Mb/s 11.08Mb/s 36Mb/s 36Mb/s 1GB/s
It has been estimated that all the books in theU.S. Library of Congress, could be stored on six(6) HVD's.
The pictures of every landmass on Earth(Google Earth for example) can be stored ontwo (2) HVD's.
With MPEG4 ASP encoding, a HVD can holdbetween 4,600 to 11,900 hours of video, whichis enough for non-stop playing for a year.
Holography allows a million bits of
data to be written and read out in
single flashes of light, enabling data
transfer rates as high as a billion bits
per second (fast enough to transfer a
DVD movie in about 30 seconds).
HVD’s have an estimated archival life
expectancy of at least 50 years or more
compared to CD/DVD archival life of 2 to
5 years (even though published life
expectancies are often cited as 10 to 25
years or longer for optical media, it
depends on the storage conditions and
quality of the disks).
HVD storage also offers interesting possibilities for data
protection. For mass production, holographic media can
be replicated very efficiently in one simultaneous
transfer from a master. But once written, the replicated
discs cannot be used as masters for further copying.
By adjusting one of its laser beams, Collinear
technology can provide a physical level of on-disk
encryption during recording and reading, which holds
great promise for digital rights management and other
applications requiring high levels of security.
Low cost materials needed to come
available which are just now happening
due to other industries utilizing new
technology.
Development of needed components,
in fields outside the storage industry,
have brought the cost down making it
financially viable to proceed.
Green lasers now used in the medical,
cable TV, and printing industries are
attractive recording sources due to their
small size, ruggedness and low cost.
Digital micro-mirror devices appearing in
new types of displays are ideal spatial
light modulators (SLM). This overhead
projector for instance uses a SLM.
The CMOS active pixel detector arrays
emerging in digital photography exhibit the
rapid access and data transfer properties
required for holography. CMOS sensors
were originally proposed for the detection
of visible light in cameras. In the
holography field, they can detect the light
patterns that are stored on the disks.
The Economist, Holographic data storage, Jul 31, 2003,
http://www.economist.com/node/1956881
General Electric Global Research
InPhase Technologies, Longmont, Colorado,
http://www.inphase-technologies.com/
Wikipedia – Holographic Data Storage,
http://en.wikipedia.org/wiki/Holographic_data_storage
Bell Laboratories Physical Sciences Research, http://www.bell-
labs.com/org/physicalsciences/projects/hdhds/1.html
How Holographic Memory Will Work by Kevin Bosner.
http://computer.howstuffworks.com/holographic-memory1.htm
Optware Corporation of America, Longmont, Colorado,
http://www.thic.org/pdf/Jul05/optware.mdeese.050719.pdf
Technology Review, July 2010,
http://www.technologyreview.com/blog/mimssbits/25418/