[citation][nom]yam[/nom]This is done by adding extra dimensions to the recording surface.
To be precise, the extra dimensions are the wavelength and polarization of light, which integrate with the familiar three spatial dimensions creates true five-dimensional recording within one volume.[/citation]
[citation][nom]bbc[/nom]The team members described what they did as adding three "dimensions" to the two spatial dimensions that DVD and CD discs already have.
They say they were able to introduce a spectral - or colour - dimension and a polarisation dimension, as well as recording information in 10 layers of the nano-rod films, adding a third spatial dimension.[/citation]
Is it possible mr. Yam to, eventually, get your act together (leaving m$ propaganda parroting aside) and report more accurately?
Funny marketing droid language from a scientists team:
"adding extra dimensions to the recording surface", "true five-dimensional recording", etc.
Traditional CD/DVD storage uses a single dimensional encoding , the parameter being pit/land length (see EFM/+). Multiple layers don't count as another dimension for encoding, just as an extension of space for the traditional one, being asynchronous, and usually accessed sequentially, not simultaneously.
So, the virtual encoding space could be, at most, theoretically extended (with polarization angle and wavelength considered) to a 3D one, considering each one being orthogonal to the other ones.
For example, WDM is already used to extend BW, squeezing more (independent) channels on one optical fiber.
But, it would be really hard to synchronize the streams, for the different discrete wavelengths, using several lasers and detectors, on different drive units (mechanics aren't sufficiently precise and reproductible), to consider them another coding space dimension. There would be just the "classic" dimension space extension, by sequentially tuning one laser to different wavelengths, similar to multiple layers usage (optical focusing on different layers). That would eliminate another "dimension".
Polarization angle could be supposedly much easier included in coding space, but as the current research is using just 2 states (this means just one supplementary bit), which hardly could be considered another "dimension". Most probably, the laser beam is polarized one way or another, for successive passes, offering just another "layer" for storage for the "classical" one dimension coding space.
All in all, we could consider the technology as an address extension (like in a MMU) - in which the current storage spiral can be selected by layer depth (current technology), wavelength, and polarization - to the effect of a much larger storage (single-dimensional) space, as it would be seen by the user.
"4D" mouse anyone? it sounds soooo cool to the noob...