Editing Holographic Versatile Disc (section)

==Technology==
[[File:HVDstruct.svg|thumb|300px|'''Holographic Versatile Disc structure'''<br/>
1.&nbsp;Green writing/reading laser (532&nbsp;nm)<br/>
2.&nbsp;Red positioning/addressing laser (650&nbsp;nm)<br/>
3.&nbsp;Hologram (data)(shown here as brown)<br/>
4.&nbsp;Polycarbonate layer<br/>
5.&nbsp;Photopolymeric layer (data-containing layer)<br/>
6.&nbsp;Distance layers<br/>
7.&nbsp;Dichroic layer (reflecting green light)<br/>
8.&nbsp;Aluminium reflective layer (reflecting red light)<br/>
9.&nbsp;Transparent base<br/>
P.&nbsp;Pit pattern<br/>
(Illustration is not to scale.)]]

Current optical storage saves one bit per pulse, and the HVD alliance hoped to improve this efficiency with capabilities of around 60,000 bits per pulse in an inverted, truncated cone shape that has a 200&nbsp;[[micrometre|μm]] diameter at the bottom and a 500&nbsp;μm diameter at the top. High densities are possible by moving these closer on the tracks: 100&nbsp;GB at 18&nbsp;μm separation, 200&nbsp;GB at 13&nbsp;μm, 500&nbsp;GB at 8&nbsp;μm, and most demonstrated of 5&nbsp;TB for 3&nbsp;μm on a 10&nbsp;cm disc.{{Citation needed|date=September 2010}}

The system used a green [[laser]], with an output power of 1 [[watt]] which is high power for a consumer device laser.  Possible solutions include improving the sensitivity of the [[polymer]] used, or developing and commoditizing a laser capable of higher power output while being suitable for a consumer unit.{{Citation needed|date=April 2007}}