| 摘要 |
PURPOSE:To enable information recording at a high density by specifying record ing conditions according to the SN ratio of the output of recording light. CONSTITUTION:A strong power laser is turned on/off according to recording signals and a medium 1 is irradiated with the beam at the time of recording with the optical recording and reproducing device, and therefore, the reflectivity changing parts according thereto remain as recording marks on the medium. The medium is irradiated with the DC light lowered in power by adjusting an ND filter 601 and the reflected light subjected to intensity modulation according to a reflectivity change is detected as photocurrent by a photodetector 7 at the time of reproducing. The photocurrent is subjected to current-voltage conversion by a preamplifier 8 and thereafter, the voltage is evaluated by a spectrum analyzer. The value of the recording light power Prec or beta satisfying the relation of equation when the SN ratio required at the time of reproducing is designated as SNR (reproducing) A and the SN ratio of the recording light as SNR (recording) R is set according to the SN ratio of the reproducing light at the time of recording and reproducing the information by using the photon mode optical recording medium. |
