Abstract
Optical storage is the leading technology for removable storage media. In order to follow the roadmap of other computer components, an annual capacity growth of 30% to 60% is needed. In the past, this was reached by decreasing the wavelength and increasing the numerical aperture; however, the next generation of DVR will approach practical limits with a numerical aperture of 0.85 and a wavelength of 405 nanometers. In order to reach capacities in the range of terabytes, volume recording is needed. We show that minor changes in the architecture of optical pick up can allow multilayer recording of a few hundred layers. New media are needed but solutions are foreseen for Read Only and Write Once media. Magneto-optic and Phase-change rewritable media offer a poor modulation to absorption ratio; therefore, multilayer rewritable media is still a challenge.
