A new super-resolution film applicable to read-only and rewritable optical disks

A new super-resolution material for optical disks is proposed which contains cobalt oxide as a main component and shows a refractive index change upon irradiation of a laser beam. This new material is different from the ones already proposed for super-resolution in that it is durable against high-power laser irradiation and thus is applicable to rewritable optical disks as well as read-only (ROM) disks. This paper reports fundamental properties of this material, C/N improvement of ROM and phase-change disks with this material, and its durability against continuous many-time readout. The potential of this technique is discussed.