01-03-2011, 11:55 AM
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Holographic Versatile Disc
Introduction to HVD
• Optical disc
• Data storage up to 3.9 TB
• Data transfer rate is 1 Gbps
• Next-next generation technology
• HVD alliance, led by Optware Corporation, Japan
• Toshiba, Panasonic, Fuji photo film, Intel Capital and Konica Minolta
Basics of Holographic Memory
• Holography is a method of recording patterns of light to produce a 3-D object
• Recorded patterns of light are Hologram
• Focused beam of light, hence Laser
• Laser beam split into two: Reference & Information
• Reference remains unchanged
• Information beam encounters object, carries that image in its waveform
• These beams intersect creating Light Interference
• This is recorded on Photographic plate generating hologram
• Shine reference/reconstruction beam on Hologram
• Reflected wave consists the light pattern of the image stored in hologram
• Reconstructed wave sent to CMOS sensor to recreate original image
Closer look at HVD
• 2-axis Holographic optics
• Optware’s Collinear Holographic optics
- Two laser beams travel in same axis
- Strikes the recording medium at the same angle
- This enables smaller pickup
• Recording layer placed between 2 substrate layers
- Dichoric mirror layer reflects blue light, which reads data encoded as interference fringes
- Aluminum reflection layer reflects red light, which acts as reference beam, tracks the reading position
The HVD system: Writing data
• Laser source
• Beam splitter/merger
• Mirrors
• Spatial light modulator (SLM)
• CMOS sensor
• Photopolymer recording medium
• Information is encoded into binary data & stored in SLM
- 1’s & 0’s converted into opaque & translucent areas on a page
- This page acts as image through which info beam is going to pass
• Firing of laser beam
- portions of light are blocked by opaque areas of the page
- portions pass through the translucent areas
- thus info beam carries image
• When reference & information beam rejoin on same axis, creating a pattern of light interference i.e. the holography data
• This joint beam carries the interference pattern to the photopolymer disc & stores it there as a hologram.