HOLOGRAPHIC MEMORY

CONTENTS INTRODUCTION BACKGROUND KEYWORDS BASIC PRINCIPLES & COMPONENTS DATA RECORDING & DATA READING TECHNICAL PROBLEMS RESEARCH WORKS NEW HOLOGRAPHIC DATA STORAGE SYSTEM CONCLUSION REFERENCES

ABSTRACT Holography goes beyond the two

dimensional approach of data storage Holography reads & writes a million bits

of data in a single flash of light Data transfer rate – billion of bits per

second Compelling choice for next generation HDSS stores 1TB of data in a sugar-cube-

sized crystal

INTRODUCTION The term Holography comes from Greek

term meaning “Whole Writing” It is a two step process It uses two laser beams Signal Beam Reference Beam Recording Medium-Litium-noibate crystal

or photoploymer Data readout depends on reference beam

BACKGROUND The principles of holography were first

put forward by Dennis Gabor The idea of HDSS was proposed by

Pieter J. Van Heerden. The technology was demonstrated by

RCA Laboratories Over the past decade IBM & Bell Labs

have led to the rise of Holographic Memory development

KEYWORDS Hologram:- an optical-interference pattern. Signal beam:- laser beam that carries data. Reference beam:- beam that paticipates in

interference & helps in data retrieval. Spatial Light Modulator:- a liquid crystal display

which displays data as pages of binay data Lithium-niobate crystal or photopolymer:- to

record the data Charge-coupled device(CCD) camera:- that

detects binary data for conversion back to original data

BASIC PRINCIPLES Object wave is superimposed by

reference wave to from hologram Reconstruction wave is used to

retrieve the data This basic principle became the

backbone of holographic data storage for digital data

BASIC COMPONENTS Blue-green argon laser Beam splitters Mirrors LCD Lens Lithium-niobate crystal or

photopolymer Charge-coupled device(CCD) camera

TECHNICAL PROBLEM WITH HDSS If too many pages are stored in the

crystal - the strength of each

hologram is diminished.-the refernce beam is not

shined at precise angle to retieve the hologram.

RESEARCH WORK ON HDSS Many companies have claimed

success in developing a photopolymer media .

InPhase has already developed HDSS named as “Tapestry”.

New Holographic Data Storage System To Be Developed Bayer AG in has developed new

HDSS,based on photosensitive plastic material.

Capacity-1000GB. Photo Addressable Polymers are

used. How does this technology work?

CONCLUSION Holographic data storage is today close enough to

commercialization,thanks to miniaturization of components. Researchers are working in this field to develop an technology to meet all challenges. With such technologies on the market, you will be able to purchase the first holographic memory players by time “Star Wars: Episode II” is released on home 3-D discs. This DVD-like disc would have a capacity 27 times greater than the 4.7-GB DVDs available today, and the playing device would have data rates 25 times faster than today’s fastest DVD players.

REFERENCES

1. “Data @ Speed Of Light” by Benoy George Thomas, in PCQUEST JUNE 2002.

2. “Holographic Memory” by Kevin Bonsor.

3. “Fundamentals Of Optics” by Francis A. Jenkins and Harvey E. White, McGraw-Hill International Editions.

4. www.howstuffworks.com