A lab in Australia is suggesting that data disks might go in a completely new direction to be able to store as much as 2000 times more data that current DVDs. The incredible jump in capacity is the result of the different physical properties of nano-particles compared to much larger atoms and bigger chunks of matter. Physics changes in many fundamental ways once you move to nano-scale sized particles.
Normal DVDs really only use 3 dimensions to store data:
1) There is the width of the “track” which depends on the wavelength of laser light being used. Original lasers started out with infrared light, but have since moved to the ultraviolet/blue end of the light spectrum as those wavelengths are much smaller allowing for the track that contains data to wind more times around the disk. Hence BluRay, uses blue lasers to squeeze more data onto disks.
2) There is no real length as the tracks are circular and go around and around in an ever-tightening spiral pattern, so there is technically only one track on the entire dvd. There is an exception if it’s a multiple-session dvd but that just leaves a small gap between tracks and then the next track resumes the same spiral pattern. The amount of times the track goes around the CD is controlled by the width of the track being burned, the thinner the track (bluray) the more data is stored on the disk.
3) Multi-layer dvds have introduced height into the equation because they allow the burning of tracks onto two layers, one layer is underneath the other and is read by changing the focus point of the laser slightly.
There are 3 physical dimensions, and in the world of normal sized particles that is the limitation. Nano particles introduce two new dimensions into the equation, color and polarity. So instead of data being a 2 bit on-off, which on a dvd is shown by grooves within a track, the data will now be able to be a different color, and have a different polarity.
The question is if computers will now move to 4-bit (on/off/colour/polarity) computing instead of 2-bit (on/off) computing.
http://www.sciencedaily.com/releases/2009/05/090520192137.htm
