A couple of years back, new break-throughs in erasable optical technologies were being announced in Japan almost weekly, but little has so far come of them, and the consensus in the optical disk industry has been that a magneto-optic technology was likely to be the first viable one for erasable optical disks. Now however, Philips NV, originator of the Compact Disk, believes it may have found a material that uses pure optics for recording and erasing. Pure optical disks record by using a high-power laser to burn minute pits into the surface of the medium, which are then read by a low power laser. Details of Philips’ technology are sketchy but the company says that it has a crystalline material in which the structure breaks down just above its melting point – to create the pit. However when the spot is reheated to just below its melting point, the crystalline structure is restored, thereby erasing the pit.