Materials for Optical Data Storage

Abstract The outstanding feature of materials research in the eighties has been the convergence of basic research and practical application, leading to ever shorter cycles of innovation. This is especially true of materials which form the basis of key technologies. The mass storage units of the next generations of computers will be based on optical processes having a storage density which exceeds that of all hitherto known storage techniques that are practicable from the technical standpoint. In view of the fact that since 1982 read‐only memories in the form of compact discs (CD‐ROM) have become very successful in the field of audio electronics, research and development are now concentrated on materials for write‐once (WORM) and erasable (EDRAW) storage systems. Suitable materials for optical data storage are substances in which data markings can be recorded and deleted respectively using semiconductor lasers. Materials development is centered on the synthesis of infrared‐absorbing dyes for WORM memories and the production of rare earth/transition metal alloys for magneto‐optical data recording. An introduction to CD‐ROM technology will be followed by an overview of the state of development of the most important storage materials which are currently available commercially, and then the properties of these materials will be discussed with reference to selected examples.