Correct me if I'm wrong here, but you are wrong.
It is still an optical drive, but instead of storing the data only on surface area, it stores it using the entire area of the media. So, in oversimplified terms you can think of it like this:
DVD/Blu-Ray store things on the surface of the optical media. So if you had (in theory) a square disc that was 4mm tall and 4mm wide and 4mm deep, you would get 16mm of usable storage area (for lack of a better term) or Height x Width (of course with dual-layer that could be X2).
If you are storing things using holographic storage methodology and you are using a square disc with the same dimensions, you would have 64mm of usable storage area or height x width x depth. This is why Maxell is planning on having 1.6TB discs by 2010, which is beyond the current theoretical limits of Blu-Ray and HD-DVD. Make sense?
And please, correct me if I'm wrong here people, because I'm not an expert in optical storage.