Holographic Versatile Disc (HVD)

[aruljothi]

It is an optical disc technology in the infant state of research, that utilizes the revolutionary collinear holography technique that has one red laser and one blue-green laser collimated into a single beam. The data that is programmed as laser interference fringes from a holographic layer at the top of the disc is read by the blue-green laser where as the servo information from the common CD style aluminum layer near the bottom is read by the red laser, which is used as the reference beam. This disc capable of storing 3.9 terabytes of data also has a dichroic mirror layer between the holographic data and servo data, that can reflect the blue-green laser while allowing the red laser to pass through. This feature has enhanced the performance of this storage media compared to the past holographic storage media where there was lot of interferences due to both the laser passing through also lacked in its compatibility to the current CD and DVD technology. The HVD disc technology has the capacity to store about 6,000 times of a CD-ROM, 830 times of a DVD, 160 times of a single layer blue-ray disc and 8 times of a normal hard drives as of 2006. It also has a transferable rate of 1 Gigabit/s.