MEDIUM AND METHOD FOR OPTICAL INFORMATION RECORDING

PURPOSE:To make possible erasing and recording at a high speed and the stable holding of information for a long period of time by irradiating two kinds of light pulses having different powers and time intervals to a thin film consists of the assem blage of the fine crystals having regular atomic configuration and in which >=2 stable states having a difference in optical characteristic exist. CONSTITUTION:The film for recording consists of a material having the compsn. which consists of a combination of >=2 components of elements exhibiting an eutectic state and is expressed as the mixture composed of the pure elements or compds. adjacent to the eutectic point on the equil. diagram thereof. The film right after the preparation consists of the assemblage of the extremely fine crystals in the amorphous film in which the elements X and Y are mixed in atomic order. The micro-part of the film is melted when the micro-part of the film is heated by irradiating the strong laser light converged to about 1mum diameter to such film. The amorphous or fine crystal state in which the elements X, Y are mixed in the part except the part irradiated with the light, designated as 1', the fine crystal of X as 2', the Y crystal mixed with the X fine crystal as 3' and the mixed state of the fine crystals of the X element and Y element contg. much X element as 4' can be transformed to each other.