PURPOSE: To prevent the filling of the existing holes at the time of hole writing and to narrow the spacing between the adjacent holes by irradiating a specific memory medium with prescribed light to induce a photochemical reaction in the guest molecules in the medium, thereby storing information.
CONSTITUTION: The memory medium 11 is formed by dispersing the guest (e.g.: 5, 10, 15, 20-tetraphenyl porphyrin) molecules in a matrix (e.g.: polymethyl methacrylate) and has the spread of the nonuniform absorption rays generated by a difference in the interaction between the matrix and the guest molecules. The light narrower then the band width of the absorption rays of the medium 11 is emitted from a laser light source 8 and the medium 11 which is impressed with a magnetic field by a magnet 23 and is cooled by a cryostat 12 is irradiated with this light by which the holes corresponding to data bits are formed. The high-density wavelength multiplex storage with high quality is thus enabled.
SHIMADA TOSHIYUKI
NISHI TOSHIHIRO
HIRATSUKA HIROAKI
