Holographic Versatile Disc

PRESENTED BY:

KAMESWARRAO.SIMHAMBHATLAEmail- kamesh.cse527@gmail.comRegd No- 06T91A0527

Dept of Computer Science & Engineering

Will discuss about

What is HVD ? Basics of Holographic memory Holographic Versatile Disc Structure Working Principle HVD Write System HVD Read System HVD capacity How HVD compares Others ? Recording errors Advantages HVD Alliance HVD Forum Conclusion References

What is HVD ?

An HVD is an advanced optical disk that’s presently in the development stage. Polaroid scientist J van Heerden was the first to come up with the idea for holographic three-dimensional storage in 1960.

Holographic Versatile Disc (HVD) is an optical disc technology still in the research stage which would hold up to 3.9 terabytes (TB) of information .

The first step in understanding holographic volatile disc is to understand what "holographic memory" means.

Basics of Holographic Memory

Holography - Method of recording patterns of light to produce a 3-D object.

Hologram-The recorded patterns of light. Greek word ‘holos’ means whole ‘gram’ means

message

Storing - A laser beam splits into- Reference beam - remains unchanged Information beam - passes through an image.

Light interference takes place when these beams intersect.

Retrieving – Reconstruction beam is send to a CMOS to sensor to recreate the image.

The same concept is used here. The information beam

encounters a pattern of light and dark areas that represent ones and zeroes

Photo courtesy Wolfgang Wieser

3-D image of the Death Star created by

holography

HVD Structure

1.Green writing/reading laser (532

nm)2. Red positioning/addressing laser (650 nm)3. Hologram (data)4. Polycarbon layer5. Photopolymeric layer (data-containing layer)6. Distance layers7. Dichroic layer (reflecting green

light)8. Aluminium reflective layer (reflecting red light)9. Transparent baseP. PIT

Continued…

1 HVD = 5800 CDs = 830 DVD =160 BLU-RAY

The surface of the Holographic Versatile Disc™ (HVD™)

Working Principle In holographic data storage, an entire page of

information is stored at once as an optical interference pattern within a thick, photosensitive optical material.

This is done by intersecting two coherent laser beams within the storage material.

The first, called the object beam, contains the information to be stored; the second, called the reference beam, is a simple light wave.

When the two combine in an optical storage medium, they change the chemical or physical construction of that medium and so store the data.

If the storage medium is then illuminated with the reference beam again, the object data beam is produced.

This technology called 'collinear holography'

Continued…

The object beam is a blue-green laser while the reference beam is a red laser which reads servo information from a regular CD-style aluminum layer.

Servo information is used to monitor the position of the read head over the disc, similar to the head, track, and sector information on a conventional hard disk drive.

Reference: http://electronics.howstuffworks.com/hvd.html

HVD Write System

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 Polymer recording medium

Laser Blue-green argon laser which is split into two

beams, a reference beam and an object beam. The interference pattern created by these two

beams forms the hologram.

Multiplexing Agent(Beam splitter/merger)

It is used to allow the laser beam to access different pages in the hologram.

Two types of multiplexing, shift multiplexing and angular multiplexing Shift Multiplexing uses a rotating disk to vary the angle of the laser beam, and so access a different view of the hologram. Angular multiplexing uses mirrors to change the angle at which the laser strikes the crystal.

Spatial Light Modulator

SLM is a 1024 * 1024

array of light or dark squares. This array represents the data to be stored, and is usually implemented by a set of pixels on an LCD.

An SLM can usually be refreshed at rates of about 1000 frames per second.

Charge Coupled Device (CCD)

CCD is an array of sensors which corresponds to the pixels on the SLM.

The CCD is used to read the interference pattern from the reference beam, and so read the information from the hologram.

The matrix construction of the CCD allows it to read all the data at once.

Typical CCD dimensions are one cm2, and typical access rates are 1000 frames / second.

Reference: http://electronics.howstuffworks.com/hvd.html

HVD Read System To read the data from an HVD, you need to retrieve the

light pattern stored in the hologram. In the HVD read system, the laser projects a light

beam onto the hologram -- a light beam -- a light beam that is identical to the reference beam.

The hologram diffracts this beam according to the specific pattern of light interference it's storing.

The resulting light recreates the image of the page data that established the light-interference pattern in the first place. When this beam of light -- the reconstruction beam -- bounces back off the disc it travels to the CMOS sensor that reproduces the page data.

Reference: http://electronics.howstuffworks.com/hvd.html

HVD Capacity

The entire US Library of Congress can be stored on six

HVDs, 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 on Earth - like the ones shown in Google Earth can be stored on two HVDs.

With MPEG4 ASP encoding, a 3.9 TB HVD can hold anywhere between 4,600-11,900 hours of video, which is enough for non-stop playing for a year.

How HVD compares Others ?

  Blu-ray HD-DVD HVD

Initial cost for recordaable disc

Approx. $18 Approx. $10 Approx. $120

Initial cost for recorder/player

Approx. $2,000 Approx. $2,000 Approx. $3,000

Initial storage capacity

54 GB 30 GB 300 GB

Read/write speed

11.08 Mbps 36.5 Mbps 1 Gbps

While HVD is attempting to revolutionize data storage, other discs are trying to improve upon current systems. Two such discs are Blu-ray and

HD-DVD, deemed the next-generation of digital storage.

Recording errors It is inevitable that storing massive amount of data will

results in errors. When data is recorded in a holographic medium, certain

factors can lead to erroneously recorded data. One major factor is the electronic noise generated by laser beams.

When a laser beam is split up (for ex., through a SLM), the generated light bleeds into place where light was need to be blocked out. Areas where zero light is desired might have minuscule amounts of laser light present which mutates its bits representation

This limitation to current laser beam and photosensitive technology is the main factor for the delay of practical holographic memory system.

In order for holographic memory systems to be practical in next generation computer systems, a reliable form of error control needs to be created.

Error control(Page label parity bits)

Data in page format requires a new way to provide error control.

Current error control methods concentrate on a stream of bits as page data is in the form of two dimensional array, error correction needs to take into account the extra dimension of bits.

When a page of data is written to the holographic media, the page is separated into smaller two dimensional arrays. These subsections are appended with an additional row and column of bits.

Continued…

The added bits calculate the parity of each row and column of data.

An odd number of bits in a row or column create a parity bit of “1” and an even number of bit create a “0”.

A parity bit where a row and column meet is also created which is called an overall parity bit.

The subsection are rejoined and sent to the holographic medium for recording.

Courtesy Optware

DVD vs. HVD: Recording-layer depthCourtesy Optware

Volumetric recording method

Advantages

High Storage capacity of 3.9 terabyte(TB) enables user to store large amount of data.

Records high-definition television (HDTV) without any quality loss.

Records one program while watching another on the disc. Edit or reorder programs recorded on the disc. Automatically search for an empty space on the disc to

avoid recording over a program. The transfer rate of HVD is up to 1 gigabyte (GB) per

second which is 40 times faster than DVD . An HVD stores and retrieves an entire page of data,

approximately 60,000 bits of information, in one pulse of light, while a DVD stores and retrieves one bit of data in one pulse of light.

limitations

In any holographic data storage system, the angle at which the second reference beam is focused on the crystal to a page of data is the crucial component. It must match the original reference beam exactly without deviation. A difference of even a thousandth of a millimeter will result in failure to retrieve that page of data.

Also, if too many pages are stored in one crystal, the strength of each hologram gets diminished.

If there are too many holograms stored on a crystal and a reference crystal used to retrieve a hologram is not focused at the precise angle, it will pick up a lot of back ground from the other holograms stored around it.

HVD Alliance

The HVD Forum

The HVD FORUM (formerly the HVD Alliance) is a coalition of corporations purposed to provide an industry forum for testing and technical discussion of all aspects of HVD design & manufacturing.

Alps Electric Corporation, Ltd. Optware Corporation CMC Magnetics Corporation Dainippon Ink and Chemicals, Inc. (DIC) EMTEC International (subsidiary of the MPO

Group) Fuji Photo Film Company, Ltd. Konica Minolta Holdings, Inc. LiteOn Technology Corporation Mitsubishi Kagaku Media Company, Ltd. (MKM)

Probable projects

Magic Sing with Holographic Data Chips

Dream Projects HVD-RW Lasers as Transmission Cables Laser Transformer Storing Holographic Energy

Experiment with a laser (US Military)

Conclusion

HVD will be next technological revolution and soon replace previous DVDs.

It is currently supported by more than 170 of the world's leading consumer electronics, personal computer, recording media, video game and music companies.

The format also has broad support from the major movie studios as a successor to today's DVD format.

Holographic Versatile Disc already has the backing of seven out of eight leading Hollywood studios. It will soon be able to enjoy a growing range of film entertainment with unsurpassed Full HD pictures and cinema-quality multi-channel sound.

Truly the best things in life come small !!!!

References

http://www.tech-faq.com/hvd.shtml.http://electronics.howstuffworks.com/hvd.html http://en.wikipedia.org/wiki/Holographic_Versatile_Dischttp://www.eweek.com/article2/0,1759,1759907,00.asphttp://www.news.com/Group-aims-to-drastically-up-disc-storage/2100-1041_3-5562599.html