| 摘要 |
PROBLEM TO BE SOLVED: To greatly change the optical property without raising the irradiation intensity of a recording laser beam, in recording/reproducing information utilizing a photoresponsive material, and to reduce a S/N ratio or to increase the recording/reproducing speed when near field light is utilized, in particular. SOLUTION: A transformation layer consisting of a material whose volume is decreased by the photo-inducement and an underlying layer consisting of a material whose optical property in reproduction is greatly different from that of the transformation layer are provided as the recording/reproducing layers. Information is recorded by the irradiation with a recording light, in which the underlying layer is approximately exposed by the decrease in volume of the transformation layer. Recorded information is reproduced on the basis of the difference between the optical properties of the transformation layer and the approximately exposed part of the under layer. Alternatively, a surface layer, which consists of a material whose optical property remarkably changes due to transformation at the time of reproduction, and which is provided with the form allowing the light transmission, and a transformation layer, which consists of a material whose volume is decreased by the photo-inducement, are provided, as the recording/reproducing layers. Information is recorded by the irradiation with a recording light, in which the surface layer is transformed due to the change in volume of the transformation layer. Recorded information is reproduced by the transformation of the surface layer. |
