Hvd Seminar

8/7/2019 Hvd Seminar

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HOLOGRAPHICS VERSATILE DISKHOLOGRAPHICS VERSATILE DISK

(HVD)(HVD)

Rashmi Routray

ENTC-ARegd No: 0701206012

Presented By :



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Outline of Seminar

o Introduction.

o A little back ground.

o What is HVD ?

o How it works.

o Advantages.

o Conclusion



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A LITTLE BACK GROUND

Polaroid 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 byrecording 500 holograms in an iron-dopedlithium-niobate crystal.



BIREN BIHARI SAHOO, ENTC(B), DRIEMS 4

Contd

The first step in understanding holographicmemory is to understand what "holographic"

means.Holography is a method of recording patternsof light to produce a three-dimensional object.The recorded patterns of light are called a

hologr am.



WHAT IS HVD ?

HVD is an optical disc , which stores 3.9terrabytes of information .

It¶s a higher version of CD¶s , DVD¶s andBLUE RAY DISC¶S , as it can store nearly200 times information then a single sidedDVD and 20 times to that of Blueray disc¶s .

Most important is it can store data in 3-D .

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Components

The components that are needed to constructHVD: Blue-green argon laser

Beam splitters to spilt the laser beam

Mirrors to direct the laser beams

LCD panel (spatial light modulator)

Lenses to focus the laser beams

Lithium-niobate crystal or photopolymer

Charge-coupled device (CCD) camera



STRUCTURE OF HVD

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HOW IT WORKS



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WORKING

When the blue-green argon laser is fired, abeam splitter creates two beams.One beam, called the signal beam, will go

straight, bounce off one mirror and travelthrough a spatial-light modulator (SLM). An SLM is a liquid crystal display (LCD) thatshows pages of raw binary data.



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Data Recor ding



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Con td

The information then is carried by the signalbeam to the light-sensitive lithium-niobatecrystal or photopolymer in place of crystal.

A second beam, called the reference beam,shoots out the side of the beam splitter andtakes a separate path to the crystal.

When the two beams meet, the interferencebeam in a specific area in the crystal -- thedata is stored as a hologram pattern that iscreated ,stores the data carried by the signal




Data Reading pr ocess:



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Contd

To read the data from an HVD, we need to retrievethe light pattern stored in the hologram.

In the HVD read system, the laser projects a light

beam onto the hologram -- a light beam that isidentical to the r efer ence beam.

The hologram diffracts this beam according to thespecific pattern.The resulting light recreates the

image of the page. When this beam of light -- ther econstr uction beam -- bounces back off the discit travels to the CMOS sensor . The CMOS sensor then reproduces the page data.



CMOS SENSOR

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Page data stored in an HVD (left) &

recreated by CMOS sensor (right)



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Wr iting Pr ocess

The process of writing information onto anHVD begins with encoding the information

into binary data to be stored in the SLM.These data are turned into ones and zeroesrepresented as opaque or translucent areason a "page" -- this page is the image that the

infor mation beam is going to pass through.






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Data Image



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ADVANTAGE

HVD can store more than 1 terabyte of data that is 200 timesmore than DVD & 20times more than Blue-ray.

Transfer rate of HVD 1Gb per second which is 40 times faster than DVD.

HVD retrieves & stores data at 60,000 bits In one single pulse of

light,i.e it stores in an overlapping pattern while a DVD storesand retrieves one bit of data in one pulse of light. .

The size and thickness of an HVD is also compatible with CDsand DVDs,it uses a thicker recording layer .

HVD stores information in entire volume of disc .

To increase capacity, holographic storage uses laser beams tostore digital data in three dimensions, rather than in twodimensions as in CD and DVD media



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CONCLUSION

HVD is a higher version of CD¶S , DVD¶S and evenBLUE RAY DISC¶S . As it provides greater flexibility instorage of data, despite high costs as a HVD can cost

around USD $120 it¶ll still establish itself as a popular option .



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REFERENCES

www.howstuffwork.com

www.wikipedia.com

www.photonics.comwww.optware.com



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