21-02-2011, 12:04 PM
presented by:
DARPAN KORAT
[attachment=8884]
Holographic Versatile Disc
What is HVD ?
Holographic Versatile Disc (HVD) is an optical disc technology which
would hold up to 3.9 terabytes (TB) of information .
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 memory systems have been around for decades. They offer far more storage capacity than CDs and DVDs -- even "next-generation" DVDs like Blu-ray -- and their transfer rates leave conventional discs in the dust.
Basics of Holographic Disk
The first step in understanding holographic disk is to understand 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
HVD Structure
Green writing/reading laser (532 nm)
Red positioning/addressing laser (650 nm)
Hologram (data)
Polycarbon layer
Photopolymeric layer (data-containing layer)
Distance layers
Dichotic layer (reflecting green light)
Aluminium reflective layer (reflecting red light)
Dimension of HVD
Working Principle
HVD uses a technology called 'collinear holography,' in which two laser rays, one is blue-green and another is red, are collimated into a single beam..
The blue-green laser reads data encoded as laser interference fringes from a holographic layer near the top of the disc while the red laser is used as the reference beam and to read servo information from a regular CDstyle aluminium layer near the bottom.
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.
DARPAN KORAT
[attachment=8884]
Holographic Versatile Disc
What is HVD ?
Holographic Versatile Disc (HVD) is an optical disc technology which
would hold up to 3.9 terabytes (TB) of information .
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 memory systems have been around for decades. They offer far more storage capacity than CDs and DVDs -- even "next-generation" DVDs like Blu-ray -- and their transfer rates leave conventional discs in the dust.
Basics of Holographic Disk
The first step in understanding holographic disk is to understand 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
HVD Structure
Green writing/reading laser (532 nm)
Red positioning/addressing laser (650 nm)
Hologram (data)
Polycarbon layer
Photopolymeric layer (data-containing layer)
Distance layers
Dichotic layer (reflecting green light)
Aluminium reflective layer (reflecting red light)
Dimension of HVD
Working Principle
HVD uses a technology called 'collinear holography,' in which two laser rays, one is blue-green and another is red, are collimated into a single beam..
The blue-green laser reads data encoded as laser interference fringes from a holographic layer near the top of the disc while the red laser is used as the reference beam and to read servo information from a regular CDstyle aluminium layer near the bottom.
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.
