Multilayered Magneto-Optical Disks for Magnetically Induced Superresolution

Magnetically induced superresolution (MSR) has been realized in magneto-optical disks using exchange-coupled magnetic multilayer film. Two new detection methods have been developed. In front aperture detection (FAD), the heated area in the light spot is optically masked. In rear aperture detection (RAD), a signal is read out only from the heated area. For higher readout power in RAD, the aperture area is sandwiched by double masks, since another mask is generated in the highest temperature region. The cut-off spatial frequency in both types of detection is more than two times higher than that in conventional detection. A high C/N of 42 dB is obtained in the MSR disks by both methods for a mark length of 0.3 µm.