Crystallization Characteristics of Phase-Change Optical Disks

Abstract
A new crystallization method for erasing recorded amorphous marks in phase-change optical disks, based on irradiation with a high power laser beam producing temperatures above the melting point of the media is proposed. Erased medium reflectivity for a prepared Sb56Te44 disk shows an intermediate value between the crystalline and amorphous states, which corresponds to a residual signal of less than -35 dB. The reflectivity after erasing is constant over a wide range of erasing power.