The scientists at IBM Corp’s Almaden Research Centre in San Jose duly demonstrated their new multi-level optical disks (CI No 2,413) without revealing too much more about the technology: the principle is simply to fuse semi-transparent recording surfaces on top of each other and focus the reading or writing laser onto the chosen surface: the company’s enthusiasm is ironic when one recalls how vehemently it rubbished optical storage in the mid-1980s, but it now claims that the impact of multi-level disks is expected to be huge, since even at today’s coarse optical data storage densities, a 10-layer disk would store some 6.5Gb of data on a standard 4.7 Compact Disk; it would also lead to dramatic increases in the capacities of the multi-disk optical libraries, and multimedia and video-game authors would also be able to use the extra capacity to add more high-quality images, sound and video to their products – but don’t hold your breath because in the lab, IBM scientists have demonstrated reading down to six layers and writing down to only four; today’s single-layer optical disks could still be usable in any future drives designed for multilevel disks, the company says but the reverse will not be possible; why does it work? Light focused on any layer is 10,000 to 100,000 times more intense than that hitting any adjacent layer, IBM found.
