Holographic Versatile Disc

Only available on StudyMode
  • Download(s) : 356
  • Published : November 5, 2011
Open Document
Text Preview
HOLOGRAPHIC MEMORY
By
Talluri Mahesh,
BL.EN.U4MEE10061.

ABSTRACT:

Devices that use light to store and read data have been the backbone of data storage for nearly two decades. Compact discs revolutionized data Storage in the early 1980s, allowing multi-megabytes of data to be stored on a disc that has a diameter of a mere 12 centimetres and a thickness of about 1.2 millimetres. In 1997, an improved version of the CD, called a digital versatile disc (DVD), was released, which enabled the storage of full-length movies on a single disc. CDs and DVDs are the primary data storage methods for music, software, personal computing and video

In order to increase storage capabilities, scientists are now working on a new optical storage method, called holographic memory that will go beneath the surface and use the volume of the recording medium for storage, instead of only the surface area. Holographic memory offers the possibility of storing 1 terabyte (TB) of data in a sugar-cube-sized crystal. A terabyte of data equals 1,000 gigabytes, 1 million megabytes or 1 trillion bytes. Data from more than 1,000 CDs could fit on a holographic memory system.

Introduction :

Devices that use light to store and read data have been the backbone of data storage for nearly two decades. Compact discs revolutionized data storage in the early 1980s, allowing multi-megabytes of data to be stored on a disc that has a diameter of a mere 12 centimetres and a thickness of about 1.2 millimetre’s. In 1997, an improved version of the CD, called a digital versatile disc (DVD), was released, which enabled the storage of full-length movies on a single disc. CDs and DVDs are the primary data storage methods for music, software, personal computing and video. A CD can hold 783 megabytes of data, which is equivalent to about one hour and 15 minutes of music, but Sony has Plans to release a 1.3-gigabyte (GB) high-capacity CD [2]. A double-sided, double-layer DVD can hold 15.9 GB of data, which is about eight hours of movies. These conventional storage mediums meet today's storage needs, but storage technologies have to evolve to keep pace with increasing consumer demand. CDs, DVDs and magnetic storage all store bits of information on the surface of a recording medium. In order to increase storage capabilities, scientists are now working on a new optical storage method, called holographic memory that will go beneath the surface and use the volume of the recording medium for storage, instead of only the surface area. Three-dimensional data storage will be able to store more information in a smaller space and offer faster data transfer times. Polaroid scientist Pieter J. van Heerden first proposed the idea of holographic (three-dimensional) storage in the early 1960s.

The first step in understanding holographic memory is to erstand what "holographic" means. Holography is a method of recording patterns of light to produce a three-dimensional object. The recorded patterns of light are called a hologram. The process of creating a hologram begins with a focused beam of light -- a laser beam. This laser beam is split into two separate beams: a reference beam, which remains unchanged throughout much of the process, and an information beam, which passes through an image. When light encounters an image, its composition changes (see How Light Works to learn about this process). In a sense, once the information beam encounters an image, it carries that image in its waveforms. When these two beams intersect, it creates a pattern of light interference. If you record this pattern of light interference -- for example, in a photosensitive polymer layer of a disc -- you are essentially recording the light pattern of the image. To retrieve the information stored in a hologram, you...
tracking img