What is a Holographic Versatile Disk?
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. An HVD would be a successor to today’s Blu-ray and HD-DVD technologies. It can transfer data at the rate of 1 Gigabit / second. The technology permits over 10 kilobits of data to be written and read in parallel with a single flash. The disk will store in terms of terabytes (TB) of data on a single optical disk.
How do they do it??
Holographic Versatile Disc (HVD) is an optical disc technology which would hold up to 3.9 terabytes (TB) of information. It employs a technique known as ‘collinear holography’, whereby two lasers, one red and one green, 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 while the red laser is used as the reference beam and to read servo information from a regular CD-style aluminum 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. On a CD or DVD this servo information is interspersed amongst the data.
Working of HVD
Challenges Ahead…..
There is no precise standard for holographic recording media
Lack of interchangeability between holographic recording devices and recording media
Holographic recording media requires flatness of the order of the optical wavelength which makes it hard to mass-produce
The system uses a green laser, with an output power of 1 watt, a high power for a consumer device laser
To develop and commoditize a laser capable of higher power output and suitable for a consumer unit
Production of holographic media requires investment in new equipment
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What are the components needed to construct an HVD reader?
A blue-green argon laser
beam splitters to spilt the laser beams
mirrors to direct the laser beams
LCD panels (spatial light modulator)
lenses to focus the laser beams
lithium-niobate crystals or photopolymers
charge-coupled device (CCD) cameras
