Holographic Versatile Disc (HVD)

It's an optical disc technology still in the childhood stages of research called as the collinear holography, would soon gain upper hand over the existing technologies like the blue-ray and HD DVD optical disc systems with respect to its storage capacity. Consisting of a blue-green laser and a red laser collimated in 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 CD-style aluminium layer near the bottom.