Future Technology

What is Holography

Holography is a technique which enables three-

dimensional images to be made. It involves the

use of a laser, interference, diffraction,

light intensity recording and suitable illumination

of the recording.

The image changes as the position and

orientation of the viewing system changes in

exactly the same way as if the object were still

present, thus making the image appear three-

dimensional.

Who invented holography?

Dennis Gabor was

a Hungarian-British electrical

engineer and physicist, most

notable for

inventing holography, for which

he later received the

1971 Nobel Prize in Physics

Three dimensional or “holographic” data

storage involves using the entire media

for storage, not just a few layers like we

currently use today.

The process is accomplished by using

two laser beams, instead of one, to

write data to the disk.

1. The object is converted into binary

code of 1’s and 0’s like we use today.

2. Next, the 1’s and 0’s are converted

into a matrix of light and dark squares.

3. Those light and dark squares are then

electronically sent to a spatial light

modulator (SLM).

4. The laser beam then shines through

the spatial light modulator (SLM).

5. Pixels of the spatial light modulator

filter (block or allow) the light thus

encoding the data into the laser beam.

SLM

Objective Lens

Cover Layer

Recording Layer

Reflective Layer

Inner: Information

Outer: Reference

Diffracted information

beam (page data)

Diffracted reference

beam (modulated)

Recorded Hologram

A green and red laser beam

are collimated in a single beam.

The green laser reads data encoded

as laser interference fringes from

a holographic layer near the top of

the disc.

A red laser is used as the reference

beam to read servoinformation from

a regular CD-style aluminium layer

near the bottom.

Red - 650 nm

Green – 532 nm

Many disk prototypes

have been looked at over

the years, however, the

industry standard has

now accepted having

the HVD disk include a

reflective layer in order to

be backward compatible

and to assist with

tracking of the write

beam. Di-isobutylacrylamide

(DBA)

A simplified HVD system

consists of the following main

components:

•Blue or green laser (532-nm

wavelength in the test system)

•Beam splitter/merger

•Mirrors

•Spatial light modulator (SLM)

•CMOS sensor

•Photopolymer recording medium

Recording Process

Media

Lens

SLM

Information Pattern

Reference

Pattern

Reconstruction Process

Media

Reconstructed

SLM

Beam SplitterLens

Reference

Pattern

Reflective

Layer

Increased storage capacity

Increased read/write speed

Longer storage life

Security

In today’s world, digital media is becoming

more and more common and is requiring

more storage to meet the new demands.

More industries are now using digital

storage than ever before.

200 DVD’s can fit on one 1 TB holographic

disk with a future capacity of 6 terabytes.

IBM's test platforms can store up to 390

bits per square micron (a micron is a

millionth of a metre). DVDs, by contrast,

have a storage density of about five bits

per square micron.

DVD DVD Blu-Ray Blu-Ray HVD

Number of Layers Single Dual Single Dual 200+/-

Recording Capacity 4.7GB 9.4GB 25GB 50GB 1TB

Data Transfer Rate 11.08Mb/s 11.08Mb/s 36Mb/s 36Mb/s 1GB/s

It has been estimated that all the books in theU.S. Library of Congress, could be stored on six(6) HVD's.

The pictures of every landmass on Earth(Google Earth for example) can be stored ontwo (2) HVD's.

With MPEG4 ASP encoding, a HVD can holdbetween 4,600 to 11,900 hours of video, whichis enough for non-stop playing for a year.

Holography allows a million bits of

data to be written and read out in

single flashes of light, enabling data

transfer rates as high as a billion bits

per second (fast enough to transfer a

DVD movie in about 30 seconds).

HVD’s have an estimated archival life

expectancy of at least 50 years or more

compared to CD/DVD archival life of 2 to

5 years (even though published life

expectancies are often cited as 10 to 25

years or longer for optical media, it

depends on the storage conditions and

quality of the disks).

HVD storage also offers interesting possibilities for data

protection. For mass production, holographic media can

be replicated very efficiently in one simultaneous

transfer from a master. But once written, the replicated

discs cannot be used as masters for further copying.

By adjusting one of its laser beams, Collinear

technology can provide a physical level of on-disk

encryption during recording and reading, which holds

great promise for digital rights management and other

applications requiring high levels of security.

Low cost materials needed to come

available which are just now happening

due to other industries utilizing new

technology.

Development of needed components,

in fields outside the storage industry,

have brought the cost down making it

financially viable to proceed.

Green lasers now used in the medical,

cable TV, and printing industries are

attractive recording sources due to their

small size, ruggedness and low cost.

Digital micro-mirror devices appearing in

new types of displays are ideal spatial

light modulators (SLM). This overhead

projector for instance uses a SLM.

The CMOS active pixel detector arrays

emerging in digital photography exhibit the

rapid access and data transfer properties

required for holography. CMOS sensors

were originally proposed for the detection

of visible light in cameras. In the

holography field, they can detect the light

patterns that are stored on the disks.

The Economist, Holographic data storage, Jul 31, 2003,

http://www.economist.com/node/1956881

General Electric Global Research

InPhase Technologies, Longmont, Colorado,

http://www.inphase-technologies.com/

Wikipedia – Holographic Data Storage,

http://en.wikipedia.org/wiki/Holographic_data_storage

Bell Laboratories Physical Sciences Research, http://www.bell-

labs.com/org/physicalsciences/projects/hdhds/1.html

How Holographic Memory Will Work by Kevin Bosner.

http://computer.howstuffworks.com/holographic-memory1.htm

Optware Corporation of America, Longmont, Colorado,

http://www.thic.org/pdf/Jul05/optware.mdeese.050719.pdf

Technology Review, July 2010,

http://www.technologyreview.com/blog/mimssbits/25418/