By Sreenath S

EC -7Roll No - 22

CEP

5 DIMENSIONAL

DVD

INTRODUCTIONAll electronic equipments need memoryIntense commercialization started from the development

of optical storageRecording signals on a medium through the use of lightMaterial used is polycarbonate plasticThe road map of optical data storage is :-

CD0.8 Gb

DVD4.7Gb

Bluray DVD50 Gb

??????5 D DVD1.6-10 Tb

Holographic Disc

100 Gb

CDWrite process -

Burning of discCauses formation of bumps and grooves

Read process - Scaning through laser Detects or reads a '1' if the laser is not reflected

(no bump) And '0' if the laser is reflected (hits a bump)

Probability of errors is highWavelenght = 780 nmChecks bits = 2/3 of the actual data

DVDIt has several layers of plastic (polycarbonate)Layers consist of :

Microscopic bumps arranged as a Single, Continuous and Extremely long spiral track of data

Once the layers are formedA thin reflective layer is sputtered onto the disc, covering the

bumps. Aluminum is used behind the inner layers, And a semi-reflective gold layer used to focus through the outer

and onto the inner layersWavelength = 640nmTwo types :

Single side Double side

Bluray DiscUtilize blue – violet laser to record and to readHybrid formatSingle layer – 25 GbDual layer – 50 Gb

Holographic DiscOptical interference pattern within photosensitive optical

materialLaser divided into two separate optical patterns dark and lightBits in parallel3D storage

5D DVD5D optical storage = 2,000 × Conventional DVDNano structured material incorporated onto a disc to

increase data capacityAditional 2 dimentions by nano materialNano structure material => “Gold Nanorods”Multiple polarizations

Effective writing at different angles in the same place

Dimensions of Data StorageDimension (D)

A parameter by which a data written on or read from an optical recording device

CDs & DVDs – 2D optical recordingDual layer DVDs & Holographic Disc – 3D storageFor greater storage we introduce more dimensions for

data storage5D = 3 spatial dimention + 1 spectral dimention + 1

polarisation

Dimensions of data storage in five dimensional optical recordingThree Spatial Dimensions: Include the three spatial dimensions

x, y and zColour dimension:

nanoparticles react to light according to their shapePolarization dimension:

Record data at two different polarization of light.

DESIGN AND FABRICATION OF STORAGE DEVICE

Basic DesignSimilar to DVD except in the gold nanorodsGold nanorods of three different sizesCoated thin glass films with the solutionUse glue to assemble a stack of three of the films, one on

top of other

a: layer gold nanorods in a polymer solution and coated on a thin layer of glass b: The spacer between two recording layers c: The polycarbonate substrate for mechanical strength to the

disc.

Gold Nanorods

Nano particles of gold in the shape of rods called

gold nanorodsDifferent sizes are used in different recording layersSpectrum and polarization sensitive nanorods react to light

depending on their shapeNanorods of different

orientations respond to different

polarizations of light

SPR of Gold NanorodsSurface plasmon resonance –

interaction between an electromagnetic wave and the conduction electrons in a metal

Incident light interacts nanostructure, photons will be released with the same frequency in all directions known as scattering.

some of the photons will be converted into phonons or vibrations of the lattice known absorption.

Nanorods the SP resonance splits into two bands: parallel (longitudinal) and perpendicular (transverse)

Effect of Coloured Lightnanoparticles react to light according to their shapeabsorbance of the light which is converted into lattice

vibrations is different for different lightEach layer has gold nanorods of a particular size that

resonate only when a particular wavelength of lightRed, Green and Blue coloured lights are used

images of SPR modes of Nano-rod for various incident

laser light at

(A) red (658 nm),

(B)green (532 nm),

(C) blue (488 nm)

Effect of Polarized LightPolarization is a property of waves that describes the orientation of their

oscillationsThe polarization can be rotated 360 degreesBy projecting light, electric field contained in the light waves aligned with

the gold nanorods. That allowed the researchers to record different layers of information at

different angles0˚ & 90˚ polarization can be done overlaped without interfering with each

other

The figure shows how we can record different

data in a same space using laser giving out light

of same wavelength but different polarization.

If Gold nanorods are aligned in the direction of polarization of the light it get heated up and melt into spheres

other nanorods remain in the original shape depending on its relative positioning with incoming light.

How it works ??..

Recording Stage 1

multiple nanorod layers are stacked between layers of transparent spacers to create a three-dimensional storage material,

The 3D can be stored in x,y & z directionAnd the laser will not interfere with the layers that are not

being read

Stage 2using different colours

and different polarizations

of light Three different colors

Red, Blue & Green9 data instead of 3 which

was in useDue to spectral dimention

onlyNanorods of different sizes respond to different

colours of light

Polarization -direction in which light waves are oscillatingNanorods of different orientations respond to different

polarizations of lightNanorods hit with the wrong colour or polarization are

unresponsive and therefore "invisible."

Reading After writing the gold nanorods permanently changes

it’s from rods to spheresfocusing light from the same laser on the bits with

much lower energyNanorods shine when they absorb the dim light,Which must be of the same wavelength and

polarization that could change their shape during recording

Advantage DisadvantageLarge storage capacityLight and CompactData security Can be manufactured on a

large scaleCompatible with existing

technology by reducing the thickness of the spacer

Storage upto 10Tb of data

Slow writing speed since the data density

Non RewriteabilityCostlyDevelop an optical decoder

Future developmentData recording could be done with a cheaper laser diode high-speed recording and readout should be possibleTest the technology on an actual DVD-sized discTry different nanorod materials. For example, he is interested

in trying silver nanorods, as they are cheaper than gold

ConclusionIntroduced two more dimensions to the

existing technologycolour dimension and polarizationIncrease the data density to attain a storage capacity of

1.5 TB in a volume of 12 cm ³proving to be a promising technology in future for bulk

data storage

Referance This paper appears in:

IEEE Applied Physics LettersDate of Publication: May 2012Author(s): Zhou, Lin National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People’s Republic of China Tang, Xia-Mei ;  Huang, Cheng-Ping ;  Zhang, Yi ;  Zhu, Yong-Yuan Volume: 100 , Issue: 22 Page(s): 221901 - 221901-4 Product Type: Journals & Magazines

^ "'5D' storage could hold 2,000 times more than 1 DVD". CBC News. Canadian Broadcasting Corporation. 2009-05-22.http://www.cbc.ca/technology/story/2009/05/22/tech-5d-storage-dvd-polarization-colours-3d-swinburne-chon-nature.html. Retrieved 2009-05-29.

Zijlstra, Peter; Chon, James; Gu, Min; Gu (2009). "Five-dimensional optical recording mediated by surface plasmons in gold nanorods". Nature 459 (7245): 410–413. 2009-05-21. DOI:10.1038/nature08053. PMID 19458719.

   

Thank you

Questions..??