seminar report_holographic memory

7/31/2019 Seminar Report_Holographic Memory

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Seminar Report

OnHOLOGRAPHIC MEMORY

Submitted by

BIBITH PV


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Seminar Report 2011-12 Holographic Memory P a g e | 2

Department of EC, Govt. Polytechnic College, Thirurangadi

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

CERTIFICATE

This is to certify that this seminar report entitled is an authentic report of the seminar presented by in

partial fulfillment of the requirements for the award of the diploma inElectronics and Communication Engineering under the Directorate of Technical Education, Government of Kerala during the year 2011-2012.

Place: Chelari Register No:

Date:

Anil Kumar. M. G Anil Kumar. M. G

Head of section in E&C Head of section in E&C

G.P.T.C Thirurangadi G.P.T.C Thirurangadi

INTERNAL EXAMINER EXTERNAL

EXAMINER


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ACKNOWLEDGEMENT

I extend my sincere gratitude towards Mr. Mohamed Shareef.K.P

(Principal, Govt. Polytechnic College, Thirurangadi) and Anil Kumar. M.G

(Head of Department, EC) for giving us his invaluable knowledge and

wonderful technical guidance

I express my thanks to all staff members of the electronics and

communication engineering department for their kind co-operation and

guidance.

I also thank all the other faculty members of EC department and my

friends for their endless help and support.

-


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ABSTRACT

Holographic data storage is a potential technology in the area of high-

capacity data storage currently dominated by magnetic and conventional optical

data storage. Magnetic and optical data storage devices rely on individual bits

being stored as distinct magnetic or optical changes on the surface of the

recording medium. Holographic data storage overcomes this limitation by

recording information throughout the volume of the medium and is capable of

recording multiple images in the same area utilizing light at different angles.

It can store data up to 1 Tb in a sugar cube sized crystal. Data from hard

drives available today can hold only 10 to 40 GB of data, a small fraction of what

holographic memory system can hold. Holographic storage has the potential to

become the next generation of storage media. Data from more than 1000 CDs can

fit into a holographic memory System. It has more advantageous than

conventional storage systems. It is based on the principle of holography .This

paper provides a description of Holographic data storage system (HDSS).

Additionally, whereas magnetic and optical data storage records

information a bit at a time in a linear fashion, holographic storage is capable of

recording and reading millions of bits in parallel, enabling data transfer rates

greater than those attained by traditional optical storage.


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CONTENTS

1. INTRODUCTION 7

2. CONCEPT OF HOLOGRAPHICMEMORY.. 8

2.1. HOLOGRAPHIC MEMORYLAYOUT.. 9

3. THEORY BEHIND HOLOGRAPHIC DATA STORAGE10

4. WORKING OF HOLOGRAPHIC DATA STORAGESYSTEM

(HDSS)

. 12

4.1. SPATIAL LIGHT MODULATOR(SLM). 13

4.2. THE COMPONENTSINVOLVED 14

4.3. WRITING.. 15

4.4. RETRIEVING /READING. 16

4.5. PAGE DATAACCESS .. 18

4.6. MULTIPLEXING 19

4.6.1. ANGULARMULTIPLEXING.. 20

4.6.2. WAVELENGTHMULTIPLEXING.. 21


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4.6.3. SPATIALMULTIPLEXING...

21

4.6.4. PERISTROPHICMULTIPLEXING. 21

4.6.5. SHIFTMULTIPLEXING

. 22

4.6.6. PHASE - ENCODEDMULTIPLEXING 23

4.7. ERRORS 24

5. A HOLOGRAPHIC DATA STORAGE DEVICE :HOLOGRAPHIC VERSATILE DISK

(HVD).. 25

5.1. SOME OF THE FEATURES OFHVD.. 25

5.2. HOLOGRAPHIC VERSATILE DISCDISCSTRUCTURE

26

5.3. SOME OF THE LIMITATIONS OFHVD.. 27

6.

SOME OF THE ADVANTAGES OF HOLOGRAPHICDATA STORAGE SYSTEM WITH RESPECT TO OTHER

DATA STORAGE

METHODS 28

7. LIMITATIONS OF HOLOGRAPHIC DATA STORAGESYSTEM

29


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7.1. OBSTACLES IN THE HOLOGRAPHIC STORAGEDEVELOPMENT

. 29

8.

COMPARISON

.. 30

9. POSSIBLEAPPLICATIONS 31

10. FUTURE DEVELOPMENT ANDCHALLENGES 32

10.1. DEVELOPMENT ANDMARKETING. 32

10.2. IN THE VIDEO GAMEMARKET.. 33

11. CONCLUSION.. 34

12. REFERENCES. 35


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1. INTRODUCTION

Devices that use light to store and read data have been the backbone of

data storage for nearly two decades. Compact discs revolutionized data storage in

the early 1980s, allowing multi-megabytes of data to be stored on a disc that has

a diameter of a mere 12 centimeters and a thickness of about 1.2 millimeters. In

1997, an improved version of the CD, called a digital versatile disc (DVD), was

released, which enabled the storage of full-length movies on a single disc.

CDs and DVDs are the primary data storage methods for music, software,

personal computing and video. A CD can hold 783 megabytes of data. A double-

sided, double-layer DVD can hold 15.9 GB of data, which is about eight hours of

movies. These conventional storage mediums meet today's storage needs, but

storage technologies have to evolve to keep pace with increasing consumer

demand. CDs, DVDs and magnetic storage all store bits of information on thesurface of a recording medium. In order to increase storage capabilities, scientists

are now working on a new optical storage method called holographic memory

that will go beneath the surface and use the volume of the recording medium for

storage, instead of only the surface area. Three-dimensional data storage will be

able to store more information in a smaller space and offer faster data transfer

times.

Scientist Pieter J. van Heerden first proposed the idea of holographic

(three-dimensional) storage in the early 1960s. A decade later, scientists at RCA

Laboratories demonstrated the technology by recording 500 holograms in an

iron-doped lithium-niobate crystal and 550 holograms of high-resolution images

in a light-sensitive polymer material. The lack of cheap parts and the

advancement of magnetic and semiconductor memories placed the development

of holographic data storage on hold.


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1.CONCEPT OF HOLOGRAPHIC MEMORYHolography is a technique, which allows recording and playback of

3-dimensional images. This is called a hologram unlike other 3-dimensional

picture hologram provide what is called parallax. Parallax allows the viewer to

move back and forth up and down and see different perspective as if the object

were actually there. In holography, the aim is to record complete wave field (both

amplitude and phase) as it is intercepted by recording medium the record in plane

may not even be an image plane. The scattered or reflected light by object is

intercepted by the recording medium the recorded completely in spite of the fact

that the detector is insensitive to the phase difference among the various part of

the optical field.

In holography, interference between the object wave and reference wave is

formed and recorded on a holographic material. The record known as hologram

(whole record) captures the complete wave, which can be viewed at the later time

by illuminating the hologram with an appropriate light beam. To this day

holography continues to provide the most accurate depiction of 3-dimensional

image in the world. In a holographic memory device, a laser beam is split in two,

and the two resulting beams in a crystal medium to store a holographic recreation

of a page of data.


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1.1. HOLOGRAPHIC MEMORY LAYOUT


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2.THEORY BEHIND HOLOGRAPHICDATA STORAGE

Holograms are photographic images that are three-dimensional and

appear to have depth. Holograms work by creating an image composed of two

superimposed 2-dimensional pictures of the same object seen from different

reference points. Holography requires the use of light of a single exact

wavelength, so lasers must be used. In reflection holograms, the kind of

holography that can be viewed in normal light, two laser beams and a

photographic plate are used to take an image of the object.

Holography is a method of recording patterns of light to produce a three

dimensional object. The patterns of light are called a hologram. The process of

creating a hologram begins with a focused beam of light -- a laser beam. This

laser beam is split into two separate beams: a reference beam, which remains

unchanged throughout much of the process, and an information beam, which

passes through an image. When light encounters an image, its composition

changes and the image is captured in its waveforms. When these two beams

intersect, it creates a pattern of light interference. If this pattern of light

interference in a layer of a disc is recorded then the light pattern of the image is

recorded.


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3.WORKING OF HOLOGRAPHIC DATASTORAGE SYSTEM (HDSS)

To record on the hologram, a page composer converts the data in the formof electric signals to optical signal the controller generate the address to access

the desired page. This results in the exposure of a small area of the recording

medium through an aperture. The optical output signal is directed to the exposed

area by the deflector. When the Blue-Argon laser is focused, a beam splitter

splits it into two, a reference beam and a signal beam. The signal beam passes

through Spatial Light Modulators (SLM) where digital information organized in

a page like format of ones and zeros, is modulated onto the signal beam as a two-

dimensional pattern of brightness and darkness. This signal beam is then purified

using different crystals. When the signal beam and reference beam meets the

interference pattern created stores the data that is carried by the different data

pages are recorded over the surface depending on the angle at which the

reference beam meet the signal beam a holographic data storage system is

fundamentally page oriented with each block of data defined by the no. of data

bits that can be spatially impressed onto the object the total storage capacity of

the system is then equal to the product of the paper size (in bits) and the no. of

pages that can be recorded. . The theoretical limits for the storage density of this

technique is approximately several tens of Terabytes (1 terabyte = 1024

gigabytes) per cubic centimeter. In 2006, In Phase Technologies published a

white paper reporting an achievement of 500 Gb/in2. From this figure we can

deduce that a regular disk (with 4 cm radius of writing area) could hold up to a

maximum of 3895.6Gb.


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4.1 SPATIAL LIGHT MODULATOR (SLM)A spatial light modulator is used for creating binary information out

of laser light. The SLM is a 2D plane, consisting of pixels which can be turnedon and off to create binary 1.s and 0.s. An illustration of this is a window and a

window shade. It is possible to pull the shade down over a window to block

incoming sunlight. If sunlight is desired again, the shade can be raised. A spatial

light modulator contains a two-dimensional array of windows which are only

microns wide. These windows block some parts of the incoming laser light and

let other parts go through. The resulting cross section of the laser beam is a two

dimensional array of binary data, exactly the same as what was represented in the

SLM. After the laser beam is manipulated, it is sent into the hologram to be

recorded. This data is written into the hologram as page form. It is called this

due to its representation as a two dimensional plane, or page of data. Spatial light

modulator is a Liquid Crystal Display panel that consists of clear and dark areas

corresponding to the binary information it represent.

Spatial light modulator is actually that device which makes holography

applicable to computers. So it is one of the important components of

Holographic Data Storage System.


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4.2. THE COMPONENTS INVOLVED

The holographic memory system is made up of the following basic

components:

a charge-coupled device lenses to focus the laser beams an LCD panel a photopolymer or lithium niobate crystal mirrors to direct the laser light beam splitters an argon laser.


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4.3. WRITING

The light from the argon laser is split in two by the beam splitter. The signal

or object beam will bounce off a mirror and pass through a spatial light

modulator or SLM (and LCD showing raw binary data as dark and clear boxes).

The signal or object beam will then carry the information from the SLM to the

crystal. The second beam or the reference beam, on the other hand, takes another

course towards the crystal and upon hitting it along with the object beam, creates

an interference pattern that will be used to store the information relayed by the

object beam in a certain location in the crystal.


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4.4. RETRIEVING / READING

The interference pattern induces modulations in the refractive index of the

recording material yielding diffractive volume gratings. The reference beam is

used during readout to diffract off of the recorded gratings, reconstructing the

stored array of bits. The reconstructed array is projected onto a pixelated detector

that reads the data in parallel. This parallel readout of data provides holography

with its fast data transfer rates (10's to 100's of MBytes/second). The readout of

data depends sensitively upon the characteristics of the reference beam. By

varying the reference beam, for example by changing its angle of incidence or

wavelength, many different data pages can be recorded in the same volume of

material and read out by applying a reference beam identical to that used during

writing. This process of multiplexing data yields the enormous storage capacity

of holography.


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An advantage of a holographic memory system is that an entire page of

data can be retrieved quickly and at one time. In order to retrieve and reconstruct

the holographic page of data stored in the crystal, the reference beam is shined

into the crystal at exactly the same angle at which it entered to store that page of

data. Each page of data is stored in a different area of the crystal, based on the

angle at which the reference beam strikes it. During reconstruction, the beam

will be diffracted by the crystal to allow the recreation of the original page that

was stored. This reconstructed page is then projected onto the charge-coupled

device (CCD) camera, which interprets and forwards the digital information to acomputer.

CCD is a 2-D array of thousands or millions of tiny solar cells, each of

which transforms the light from one small portion of the image into electrons.

Next step is to read the value (accumulated charge) of each cell in the image. In a

CCD device, the charge is actually transported across the chip and read at one

corner of the array. An analog-to-digital converter turns each pixel's value into adigital value. CCDs use a special manufacturing process to create the ability to

transport charge across the chip without distortion. This process leads to very

high-quality sensors in terms of fidelity and light sensitivity. CCD sensors have

been mass produced for a longer period of time, so they are more mature. They

tend to have higher quality and more pixels.

The key component of any holographic data storage system is the angle atwhich the second reference beam is fired at the crystal to retrieve a page of data.

It must match the original reference beam angle exactly. A difference of just a

thousandth of a millimeter will result in failure to retrieve that page of data.


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4.5. PAGE DATA ACCESS

Because data is stored as page data in a hologram, the retrieval of this data

must also be in this form. Page data access is the method of reading stored data

in sheets, not serially as in conventional storage systems. It was mentioned

in the introduction that conventional storage was reaching its fundamental limits.

One such limit is the way data is read in streams. Holographic memory reads

data in the form of pages instead. For example, if a stream of 32 bits is sent

to a processing unit by a conventional read head, a holographic memory

system would in turn send 32 x 32 bits, or 1024 bits due to its added

dimension. This provides very fast access times in volumes far greater than

serial access methods. The volume could be one Megabit per page using a SLM

resolution of 1024 x 1024 bits at 15-20 microns per pixel.


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4.6. MULTIPLEXING

Once one can store a page of bits in a hologram, an interface to a

computer can be made. The problem arises, however, that storing only one page

of bits is not beneficial. Fortunately, the properties of holograms provide a

unique solution to this dilemma. Unlike magnetic storage mechanisms which

store data on their surface, holographic memories store information throughout

their whole volume. After a page of data is recorded in the hologram, a small

modification to the source beam before it reenters the hologram will record

another page of data in the same volume. This method of storing multiple pages

of data in the hologram is called multiplexing. The thicker the volume becomes,

the smaller the modifications to the source beam can be.

There are five types of multiplexing :

1. Angular Multiplexing2. Wavelength Multiplexing3. Spatial Multiplexing4. Peristrophic Multiplexing5. Shift Multiplexing6. Phase-Encoded Multiplexing


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4.6.1. ANGULAR MULTIPLEXING

When a reference beam recreates the source beam, it needs to be at thesame angle it was during recording. A very small alteration in this angle will

make the regenerated source beam disappear. Harnessing this property, angular

multiplexing changes the angle of the source beam by very minuscule amounts

after each page of data is recorded (see figure 2). Depending on the sensitivity of

the recording material, thousands of pages of data can be stored in the same

hologram, at the same point of laser beam entry[10]. Staying away from

conventional data access systems which move mechanical matter to obtain data,

the angle of entry on the source beam can be deflected by high-frequency sound

waves in solids[10]. The elimination of mechanical access methods reduces

access times from milliseconds to microseconds.


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4.6.2. WAVELENGTH MULTIPLEXING

Used mainly in conjunction with other multiplexing methods, wavelengthmultiplexing alters the wavelength of source and reference beams between

recordings. Sending beams to the same point of origin in the recording medium at

different wavelengths allows multiple pages of data to be recorded. Due to the

small tuning range of lasers, however, this form of multiplexing is limited on its

own.

4.6.3. SPATIAL MULTIPLEXING

Spatial multiplexing is the method of changing the point of entry of source

and reference beams into the recording medium. This form tends to break away

from the non-mechanical paradigm because either the medium or recording

beams must be physically moved. Like wavelength multiplexing, this iscombined with other forms of multiplexing to maximize the amount of data

stored in the holographic volume. Two commonly used forms of spatial

multiplexing are peristrophic multiplexing and shift multiplexing.

4.6.4. PERISTROPHIC MULTIPLEXING

This form of spatial multiplexing rotates the recording medium as the light

source beams remain in fixed positions[10]. For instance, a holographic cube

could be rotated so each of its six sides could take in a source beam. This would

provide six times the number of pages which could be stored in the volume.


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Certain problems arise when implementing this method of multiplexing. The

rotational axes needs to be positioned in a way which does not interfere with the

laser beams. As with all spatial multiplexing, bringing the recording media back

to its original position for data retrieval would need to be very precise. This ismuch easier to maintain when the media remains static.

4.6.5. SHIFT MULTIPLEXING

Shift multiplexing alters the point of entry on one surface of the recording

media. The recording optics or media could be repositioned to allow the source

beam to enter multiple positions on a surface. Depending on the size of the laser

beam and thesensitivity of the recording media, the points of entry the source

beam takes into it can be immense[10]. This form of multiplexing combined with

peristrophic multiplexing could cover a very large percentage of the hologram.


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4.6.6. PHASE - ENCODED MULTIPLEXING

The form of multiplexing farthest away from using mechanical means to

record many pages in the same volume of a holograph is called phase-encoded

multiplexing. Rather than manipulate the angle of entry of a laser beam or

rotate/translate the recording medium, phase-encoded multiplexing changes the

phase of individual parts of a reference beam. The main reference beam is split

up into many smaller partial beams which cover the same area as the original

reference beam. These smaller beamlets vary by phase which changes the state of

the reference beam as a whole. The reference beams intersects the source beam

and records the diffraction relative to the different phases of the beamlets. The

phase of the beamlets can be changed by nonmechanical means, therefore

speeding up access times.

COMBINING MULTIPLEXING METHODS

No single multiplexing method by itself is the best way to pack a

hologram full of information. The true power of multiplexing is brought out in

the combination of one or more methods. Hybrid wavelength and angular

multiplexing systems have been tested and the results are promising. Recent tests

have also been formed on spatial multiplexing methods which create a hologram

the size of a compact disc, but which hold 500 times more data.


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4.7. ERRORS

When data is recorded in a holographic medium, certain factors can lead

to erroneously recorded data. One major factor is the electronic noise generated

by laser beams. When a laser beam is split up (for example, through a SLM ), the

generated light bleeds into places where light was meant to be blocked out. Areas

where zero light is desired might have minuscule amounts of laser light present

which mutates its bit representation. For example, if too much light gets recorded

into this zero area representing a binary 0, an erroneous change to a binary 1

might occur.


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4. A HOLOGRAPHIC DATA STORAGEDEVICE : HOLOGRAPHIC VERSATILE

DISK (HVD)

HDV(Holographic Versatile Disc) A high-capacity optical disc is the one that

combines single beam holographic storage and DVD technologies to provide

cartridge capacities reaching 1TB and beyond. Hence the holographic Versatile

Disk offer far more storage and transfer capacity than CDs and DVDs and even

"next-generation" DVDs like Blu-ray.

5.1. SOME OF THE FEATURES OF HVD

Unlike current CD and the DVD drive technology the HVDs have thecapacity to hold up to 300 gigaabytes of information.

The holographic versatile disc has a transfer rate of 1 Gbit/s. Working of HVD is almost similar to the holographic data storage

mechanism.


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5.2. HOLOGRAPHIC VERSATILE DISC DISC

STRUCTURE

The figure above shows the cross section of an HVD disc.

As seen in this diagram, holographic recording layer is formed on top of a

reflective layer. The simple optical setup of Collinea Technology has allowed the

HVD disc to have a reflective layer on the substrate and address pits formed on

this layer. This configuration is the key to apply Collinear Technology to

commercial HVD products. These address pits and the servo technology to read

them guarantee the interchangeability of HVD discs, ruggedness against

vibration in the real environment, wide system margin against variety of HVD

discs from different manufacturers. Of course the servo information also make

random access easy.

The servo technology and the address pits are, in fact, not different from

those used in the current CD and DVD players and disks. The laser which is used

to read address pits is 650nm red laser, also common with DVD players in the

market.


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Another layer called Dichroic Mirror Layer_Eis placed between the

holographic recording layer and the substrate to block the green or blue laser,

which are used to read/write holographic information, to reach address pits, thus

eliminates noise. In short, HVD is a disc the holographic recording layer ofwhich is formed on top of a conventional optical disk.

5.3. SOME OF THE LIMITATIONS OF HVD

Holographic consumer products need to be very cheap in order to compete

with DVD drives, which currently cost much higher, because of the much higher complexities in working and development. Holographic memory discs have been notably thicker than CDs and DVDs. Since HVDs are composed of very complex mechanisms and an investment

of

over $100 m (778 m) is typically required to develop a new platform.


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5.SOME OF THE ADVANTAGES OFHOLOGRAPHIC DATA STORAGE

SYSTEM WITH RESPECT TO OTHER

DATA STORAGE METHODS

Three-dimensional data storage will be able to store more information in asmaller space and offer faster data transfer times.

Unlike other technologies that record one data bit at a time, holographyrecords and reads more than a million bits of data with a single flash of light.

This enables significantly higher transfer rates than current optical storagedevices.

High storage densities and fast transfer rates, combined with durable, reliable,low-cost media, mean that holography is poised to become a compelling

choice for next-generation storage. In addition, the flexibility of the technology allows a wide variety of

holographic storage products to be developed, ranging from handheld devices

for consumers to storage products for enterprises.

IT can be imagined having 50 hours of high-definition video on a single disc,5000 songs on a postage stamp, or 500 000 X-rays on a credit card.

an entire page of data can be retrieved quickly at one time.


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6.LIMITATIONS OF HOLOGRAPHICDATA STORAGE SYSTEM

In any holographic data storage system, the angle at which the secondreference beam is focused on the crystal to a page of data is the crucial

component. It must match the original reference beam exactly without

deviation. A difference of even a thousandth of a millimeter will result in

failure to retrieve that page of data.

Also, if too many pages are stored in one crystal, the strength of eachhologram gets diminished.

If there are too many holograms stored on a crystal and a reference crystalused to retrieve a hologram is not focused at the precise angle, it will pick up

a lot of back ground from the other holograms stored around it.

7.1 OBSTACLES IN THE HOLOGRAPHIC STORAGEDEVELOPMENT

The absence of a suitable holographic material which should have high signalto noise ratio.

Optical technology has also been experiencing a setback because of the heavycompetition from semiconductor and magnetic technologies.

Holographic system requires lens system for imaging the signal from theSLM to the detector array or for steering the angle of the reference beam.

Optics cause holographic memories to be both bulky and expensive. The laser must have sufficient power at the required wavelength and should

be small enough to fit into a reasonable sized system.

7.COMPARISON


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While HVD is attempting to revolutionize data storage, other discs are

trying to improve upon current systems. Two such discs are Blu-ray and HD-

DVD, deemed the next-generation of digital storage. Both build upon currentDVD technology to increase storage capacity. All three of these technologies are

aiming for the highdefinition video market, where speed and capacity count.

Blu-ray HD-DVD HVD

Initial cost for

recordabledisc

Approx. $18 Approx. $10 Approx. $120

Initial storage

capacity 54 GB 30 GB 300 GB

Initial cost for

recorder/player

Approx.$2,000

Approx.$2,000

Approx.$3,000

Read/write speed 36.5 Mbps 36.5 Mbps 1 Gbps

HVD is still in the late stages of development and it has probably noticed

that the projected introductory price for an HVD is a bit steep. An initial price of

about $120 per disc will probably be a big obstacle to consumers. However, this

price might not be so insurmountable to businesses, which are HVD developers'

initial target audience. Optware and its competitors will market HVD's storage

capacity and transfer speed as ideal for archival applications, with commercial

systems available as soon as late 2006. Consumer devices could hit the market

around 2010.

8.POSSIBLE APPLICATIONS


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There are many possible applications of holographic memory.

Holographic memory systems can potentially provide the high-speed transfersand large volumes of future computer systems. One possible application is data

mining. Data mining is the process of finding patterns in large amounts of data.

Data mining is used greatly in large databases which hold possible patterns

which cant be distinguished by human eyes due to the vast amount of

data. Some current computer systems implement data mining, but the mass

amount of storage required is pushing the limits of current data storage

systems. The many advances in access times and data storage capacity that

holographic memory provides could exceed conventional storage and speed up

data mining considerably. This would result in more located patterns in a shorter

amount of time.

Another possible application of holographic memory is in petaflop

computing. A petaflop is a thousand trillion floating point operations per

second. The fast access in extremely large amounts of data provided by

holographic memory systems could be utilized in petaflop architecture. Clearly

advances are needed in more than memory systems, but the theoretical

schematics do exist for such a machine. Optical storage such as holographic

memory provide a viable solution to the extreme amount of data which is

required for petaflop computing.

Holographic memory can be used as extended DRAM with 10ns accesstime, Hard disk drives ,CD ROMs of large storage capacity and rockmounted

(combining numerous DASDs) of petabytes storage capacity.


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10. FUTURE DEVELOPMENT AND

CHALLENGES

In the past, the realization of holographic data storage has been frustratedby the lack of availability of suitable system components, the complexity of

holographic multiplexing strategies, and perhaps most importantly, the absence

of recording materials that satisfied the stringent requirements of holographic

data storage. Recently the development of practical components for holographic

systems has rekindled interest in this technology. While the development of the

needed components has been accomplished for non holographic markets, the

volume of these markets is expected to lead to low-cost, reliable components for

holographic data storage. DVD-R (red 680nm) and DVD-B (blue 405-407nm)

have been developed for the optical storage market place. These recording

sources have the desired characteristics for holographic storage and are attractive

due to their small size, ruggedness, and low cost.

The InPhase Technology team has invented several multiplexing

techniques that yielded a simple, easily implementable architecture for

holographic storage systems. Changes in both the quality of the laser beam and

recording material are being researched, but these improvements must take into

consideration the cost-effectiveness of a holographic memory system. These

limitations to current laser beam and photosensitive technology are some of the

main factors for the delay of practical holographic memory systems.

10.1. DEVELOPMENT AND MARKETING

At the National Association of Broadcasters 2005 (NAB) convention in

Las Vegas, InPhase conducted public demonstrations of the worlds first

prototype of a commercial storage device at the Maxell Corporation of America


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booth. The three main companies involved in developing holographic memory,

as of 2002, were InPhase and Polaroid spinoff Aprilis in the United States, and

Optware in Japan. Although holographic memory has been discussed since the

1960s, and has been touted for near-term commercial application at least since2001, it has yet to convince critics that it can find a viable market. As of 2002,

planned holographic products did not aim to compete head to head with hard

drives, but instead to find a market niche based on virtues such as speed of

access.

InPhase Technologies, after several announcements and subsequent delays

in 2006 and 2007, announced that it would soon be introducing a flagship

product. InPhase went out of business in February 2010 and had its assets seized

by the state of Colorado for back taxes. The company had reportedly gone

through $100 million but the lead investor was unable to raise more capital. In

April 2009, GE Global Research demonstrated their own holographic storage

material that could allow for discs that utilize similar read mechanisms as those

found on Blu-ray Disc players.

10.2. IN THE VIDEO GAME MARKET

Some have speculated that Nintendo will be the first video game console

maker to implement holographic data storage due to the uncovering of a Joint

Research Agreement between InPhase and Nintendo. Nintendo is also mentioned

in the patent as a joint applicant: "... disclosure is herein made that the claimed

invention was made pursuant to a Joint Research Agreement as defined in 35

U.S.C. 103 (c)(3), that was in effect on or before the date the claimed invention

was made, and as a result of activities undertaken within the scope of the Joint

Research Agreement, by or on the behalf of Nintendo Co., and InPhase

Technologies, Inc." It is still unclear whether InPhase's closure has affected this

rumor in any way.


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11. CONCLUSIONThe future of holographic memory is very promising. The page access

of data that holographic memory creates will provide a window into next

generation computing by adding another dimension to stored data. Finding

holograms in personal computers might be a bit longer off, however. The large

cost of high-tech optical equipment would make small-scale systems

implemented with holographic memory impractical.

Holographic memory will most likely be used in next generation

super computers where cost is not as much of an issue. Current magnetic

storage devices remain far more cost effective than any other medium on the

market. As computer systems evolve, it is not unreasonable to believe that

magnetic storage will continue to do so. As mentioned earlier, however, these

improvements are not made on the conceptual level. The current storage in a

personal computer operates on the same principles used in the first magnetic data

storage devices. The parallel nature of holographic memory has many potential

gains on serial storage methods. However, many advances in optical

technology and photosensitive materials need to be made before we find

holograms in computer systems.


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12. REFERENCES1. Computer organisation by Carl hamacher.2. Holographic memory, by John Sand.3. Kevin Kurtis from Iphase technologies.4. en.wikipedia.org5. Chip magazine6. PC Quest Magazine7. www.softpedia.com.8.

http://www.riedelit.com/Data_Recovery_Technical_Guide.html

9. http://www.usbyte.com/common/optical_data_storage_systems.html10.www.howstuffworks.com/11.www.mediastoragedevices.com/holographic-versatile-disc.html12.http://www.answers.com/topic/holographic-versatile-disc13.http://www.hvd-forum.org/abouthvd/technology.html14.http://www.howstuffworks.com15.http://www.stanford.edu/~svngam/
http://www.softpedia.com/http://www.riedelit.com/Data_Recovery_Technical_Guide.htmlhttp://www.usbyte.com/common/optical_data_storage_systems.htmlhttp://www.howstuffworks.com/http://www.howstuffworks.com/http://www.mediastoragedevices.com/holographic-versatile-disc.htmlhttp://www.mediastoragedevices.com/holographic-versatile-disc.htmlhttp://www.answers.com/topic/holographic-versatile-dischttp://www.answers.com/topic/holographic-versatile-dischttp://www.hvd-forum.org/abouthvd/technology.htmlhttp://www.hvd-forum.org/abouthvd/technology.htmlhttp://www.howstuffworks.com/http://www.stanford.edu/~svngam/http://www.stanford.edu/~svngam/http://www.stanford.edu/~svngam/http://www.howstuffworks.com/http://www.hvd-forum.org/abouthvd/technology.htmlhttp://www.answers.com/topic/holographic-versatile-dischttp://www.mediastoragedevices.com/holographic-versatile-disc.htmlhttp://www.howstuffworks.com/http://www.usbyte.com/common/optical_data_storage_systems.htmlhttp://www.riedelit.com/Data_Recovery_Technical_Guide.htmlhttp://www.softpedia.com/

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