three-dimensional data storage

8/2/2019 Three-Dimensional Data Storage

1/21

Three-Dimensional Data

Storage


2/21

Todays Data Storage Medium

Maximum data storage limits we have reached

today:-

15.9G.B on a double-layer, doubled sided

DVD. 750 GB on SATA hard disk.

Is this enough??


3/21

Holographic Storage Technology

Holographic storage is a breakthrough technology

that stores information within its volume.

It utilizes the space within special types of crystalswith optical characteristics, which are very similar

those used to create 3D holograms.

It has ability to accurately focus the reference laser

on the exact position within the crystal to retrieve

that page of information.


4/21

Holographic storage is an optical technology

that allows 1 million bits of data to be

written or read in a single flash of light. Imagine 2GB of data on a postage stamp,

20GB on a credit card, or 200 GB on a disc.

1 TB on multi-layer discs. Combining high storage densities and fast

transfer rates with durable, reliable, low

cost media, Holographic technology is

poised to become a compelling choice fornext-generation storage and content

distribution needs.


5/21

Holographic storage incorporates the use of

laser, optics, images sensors and specialcrystals that respond to laser light.

For recording, it utilizes intersecting signaland reference laser beams to store data in a

number of 3D hologram images capable ofsaving hundreds of data pages in a singlelocation.

Since it involves no moving parts,

holographic data storage will be far morereliable than existing hard disk

technologies.


6/21

Two Coherent beams, one carrying a page of information, interfere

within a photosensitive material to record a hologram.

SLM:-Spatial Light Modulator.

How To Write Data?


7/21

Ref: http://en.wikipedia.org/wiki/Holography


8/21

Illuminating the hologram with the reference beam reconstructs a copy

of the original information bearing beam for capture with a detector

array.

How To Read Data?


9/21

Illuminating multiple stored holograms with a new page of search

information reconstructs all of the reference beams, computing in

parallel the correlation between data and each of the stored pages.

Parallel Reading


10/21

1. Green writing/reading laser

(532 nm)

2. Red positioning/addressing

laser (650 nm)

3. Hologram (data)

4. Polycarbonate layer

5. Photo polymeric layer (data)6. Distance layers

7. Diachronic layer (reflecting

green light)

8. Reflective layer (reflecting redlight)9. Transparent base

P. PIT

Holographic Versatile Disc structure

This type of disc has transfer rate of 1G bit/s.

Ref: www.holographicversatile.com


11/21

Advantages

In contrast to surface storage techniques such as CD/DVD,where the density is inversely proportional to the square ofthe wavelength, holographic is a volumetric technique,making the density proportional to one over the third powerof the wavelength.

Laser beams can be moved with no mechanical components,allowing access data times of the order of 10 micro seconds,faster than any conventional disk drive will ever able torandomly access data.

Holographic data storage has shown the capability of rapidparallel search through the stored data via associativeretrieval.

By varying the reference beam angle, wavelength or mediaposition many different holograms can be recorded in thesame volume of material.


12/21

Fluorescent MultiLayer StorageTechnology

The concept of multi-layer reflective optical

discs has been proposed by Philips and

IBM. It is a unique breakthrough, solving the

problems of signal degradation associated

with reflective optical disc technologies of

CD/DVD.


13/21

With FMD/C technology, each storage layer

is coated with a transparent fluorescent

material rather than metallic layer of

CD/DVD.

Backward compatibility with existingCD/DVD media.

It allows parallel reading.

A sequence of bits is recorded not along a

track but deep into layers.


14/21

According to FMD-ROM developers, even with a hundred layers a useful

signal will be acceptable.

In case of CD/DVD,

due to multiple

interferences theprocess of reading data

from discs becomes

more complicated as

the number of layers

increases.


15/21

How to write data?

The first principle (thermal) implies usage ofmaterial which possesses fluorescent propertiesfrom the beginning (logical one). And whenrecording those segments which are thermally

acted upon with a laser lose these properties(logical zero). (WORM)

The second principle (chemical) means usage of amaterial that doesn't possess fluorescent propertiesform the beginning. When acting upon with a laser

a photochemical reaction starts, and the materialgets fluorescent properties. There, a low-powerlaser is enough, or even a usual LED.


16/21

Fluorescent Multi-layer Disc


17/21

Fluorescent Multilayer card

The fluorescent multilayer card is a card containing

a square shaped clear part which has multiple layers

each with a different fluorescent material that

reflects light at a different frequency than the otherlayers, so that the number of layers is limited only by

the thickness of the card. A card with the data area

roughly 25 mm or one inch wide, able to hold 10 GB

of data.


18/21

FMD/C Advantages

The multi-layer system is opticallytransparent and homogeneous.

No absorption for the emitted signal

fluorescent light.The emitted fluorescent light from any

given layer is non - coherent,

eliminating the problem of multipleinterference.

FMD technology is compatible withcurrent CD and DVD formats.


19/21

Future Scope


20/21

A holographic format, Tapestry Media,capable of storing up to 1.6TB with a datatransfer rate of 120 MB/s. Hitachi Maxell,

Ltd. plans to enter the market by offering300 GB discs with a data transfer rate of 20MB/s.

A 50 GB prototype disc was demonstratedat the COMDEX industry show in November2000. First generation FMDs were to use650 nm red lasers, yielding roughly 140 GB

per disc. Second and third generation FMDswere to use 405 nm blue lasers, givingcapacities of up to a TB.


21/21

Thank You

three-dimensional data storage

Documents