| 摘要 |
PURPOSE:To easily perform multiplex recording with very high density by making plural beams of light with different wavelength incident on a first dual grating having a diffraction grating of equal pitch and making them inci dent on the recording layer of an optical information recording medium consisting of a photochromic material by stopping them to one beam of light. CONSTITUTION:Since the entire plane of the diffraction grating 4a is formed in equal pitch, the angle of diffraction is decided with the wavelength of a laser beam. Then, the emission optical axis 11 of light emitted from the first dual grating 4 is stopped to one beam of light by varying the arranging interval of three semiconductor lasers 2, and the emission optical axis 11 is adjusted so as to align with the optical axis of a first lens 5. The light changed to one beam of light and including three wavelengths lambda1-lambda3 is converged with the first lens 5, and is made incident on an optical disk 6 having the recording layer 6a consisting of the photochromic material. Thereby, it is possible to easily record an independent signal fitted in each wavelength on respective recording layer 6a. |
