Abstract

Phase-change media, utilizing the switching between amorphous states and crystalline states induced by the heating of a focused laser beam for information storage, have been the subject of research for many years. The major challenge is to develop materials having appropriate crystallization kinetics so that the amorphous state can be crystallized in a matter of nanoseconds under the influence of the heating laser beam and yet remain stable at operating and keeping temperatures. For erasable operation, the kinetics should also allow the quenching of the material from the molten state produced by the heating laser beam into the amorphous state. This requires the crystallization rate at just below the melting point to fall within a narrow range determined by the maximum crystallization rate allowed by practical considerations and the cooling rate of the media.

© 1987 Optical Society of America