Holographic versatile disk

HOLOGRAHIC VERSATILE DISK

GUIDED BY:

MRS. V. SUDHARSHANI

PRESENTED BY:

K. SHAMINI

CONTENTS:

• Introduction

• Need of HVD

• What is HVD?

• Basics of holographic memory

• Technology used in HVD

• Structure of HVD?

• Writing data

• Reading data

• Advantages, disadvantages and applications of

HVD

• Facts

• Future aspects

• conclusion

INTRODUCTION

• HVD is an advanced optical disk that’s presently

in the development stage.

• Storage capacity: 1 terabyte (Tb)

• Data transfer rate: 1 gigabit per second

• The technology permits over 10 kilobits of data to

be written and read in parallel with a single flash.

Need for HVD?

Types of optical

storageCapacity

Writing/

Reading

Speed

Discs

Approx.

Cost

Recordable

Player

Approx.

Cost

Holographic

Versatile

Discs

(HDSS)

HVD 300 GB–

1.6 TB1 GB/s $120 $3000

Blu-ray

Discs BD

25 GB–

50 GB

36.5

Mb/s$18 $2000

Digital

Versatile

Discs

DVD–

HD-

5 GB–

30 GB

36.5

Mb/s$10 $2000

Compact

Discs CD

783 MB–

1.3 GB

36.5

Mb/s$4 $200

What is HVD?

• Holographic versatile disk is a holographic storage

format that looks like a DVD but is capable of storing

far more data.

• Prototype HVD devices have been created with a

capacity of 3.9TB and a transfer rate of 1GBPS.

• 1HVD=5,500 CD’s=830 DVD’s=160 Blu-ray discs.

• Uses laser beams to store data in 3D.

Basics of holographic memory

• Holography is a method of recording patterns of light to

produce a 3D object .

• Recorded patterns of light is called a hologram.

• Creation of a hologram begins with a focused beam of light,

a laser.

• Laser splits up into two beams:

1. Reference beam

2. Information beam

• When light encounters an image its composition changes.

• When the information beam encounters an image, it

carries that image in its waveforms

•When the two beams intersect, it creates a pattern of

light interference and that can be recorded on the

photosensitive polymer layer of the disk.

• To retrieve the information stored in a hologram,

shine the reference beam onto the hologram. When it

reflects off the hologram, it holds the image pattern of

the stored image.

• This reconstruction beam is then sent to a CMOS

sensor to recreate the original image.

Technology used in HVD

• Collinear holography- the laser beams are collimated.

• Blue-green laser reads the data encoded in the form of

laser interference.

• Red laser serves the purpose of reference beam and to

read servo info.

• A layer of dichroic mirrors, between the holographic

and servo data layer reflects the blue-green laser

beam, letting only the red laser to pass through it to

reach the servo information .

• The concepts of collinear holographic memories

are:

• To increase the recording capacity, thick volume-

recording media is used.

• Optical disk is pre-formatted with addresses and

optical servo information.

• The beam for the optical servo is utilized to

provide backward compatibility with d existing CD’s

and DVD’s.

Structure of HVD

The holographic versatile disk structure consists of the

following components:

• Green writing/reading laser (532nm)

• Red position/addressing laser (650nm)

• Hologram (data)

• Polycarbon layer

• Photo polymeric layer (data-containing layer)

• Distance layers

• Dichroic layer (reflecting green light)

• Aluminum reflective layer (reflecting

red light)

• Transparent base

Writing Data

• a simplified HVD system consists of the following main

components:

• Blue or green laser (532nm wavelength)

• Beam splitter/merger

• Mirrors

• Spatial light module (SLM)

• CMOS sensor

• Photopolymer recording medium

Information is encoded into binary and is stored in the

SLM.

These data are turned into ones and zeros represented as

opaque or translucent areas on a ‘page’.

When the information beam passes through the SLM,

portions of the light are blocked by the opaque areas of the

page, and portions pass through the translucent areas.

When the reference beam and the information beam rejoin

on the same axis, they create a pattern of light interference,

the holography data.

This interference pattern is stored in the photopolymer area

of the disc as a hologram.

Reading Data:

• To read, we have to retrieve the light pattern stored in the

hologram

• Laser is projected onto the hologram –a light beam that is

identical to the reference beam.

• The hologram diffracts this beam according to the specific

pattern of light interference is storing.

• The resulting light recreates the image of the page that

established the light-interference pattern-reconstruction

beam.

•The CMOS sensor then reproduces the page data.

•The reconstruction beam-bounces back off the disc, it travels to the

CMOS sensor.

Advantages, Disadvantages And Applications

• Advantages:

• More storage capacity

• Data transfer date is high

• Disadvantages:

• Initial price of the player and disk are high

• Price and data storage not confirmed still in R & D

• Applications:

• Used for storing large amounts of data most likely for large

companies

• Could be the most efficient way to back up information in the

near future.

Facts

• The entire US library of congress can be stored on six

HVD’s, assuming that every book has been scanned in

the text format. The library of congress is the largest

in the world and contains over 130 million items.

• The pictures of every landmass of earth-like the one

shown in the Google earth can be stored on two

HVD’s.

Future Aspects

• Have tremendous implications in the commercial,

industrial and d-cinema realms.

• Will find wide use for backing up and archiving the

media libraries, including the one at the Hollywood

studios.

Conclusion

• The HDV’s will soon replace DVDs and blu-ray

disks.

• Currently supported by more than 170 of the

worlds leading consumer electronics, personal

computer, recording media, video game and music

company.

• The format has also broad support from the major

movie studios as a successor to today's DVD and

blu-ray disk format.