IRISTER - MAGNETOOPTICAL DISK FOR MAGNETICALLY INDUCED SUPERRESOLUTION

IRISTER (IRIS Thermal Eclipse Reading) is a remarkable technique for a chieving superresolution in optical disks. Two applications of IRISTER are Magnetically induced SuperResolution (MSR) and Premastered optica l disk by SuperResolution (PSR). Magnetically induced SuperResolution (MSR) has been realized in magneto-optical disks using exchange-couple d magnetic multilayer films. Two new detection methods have been devel oped. In the front aperture detection (FAD) method, the heated area in the light spot works as an optical mask so that the signal is read ou t only from the remaining crescent-shaped area in the spot. In the rea r aperture detection (RAD) method, the signal is read out only from th e heated area. The cutoff spatial frequency for both types of detectio n 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 mum, which is much shorter than the optical limit. Premastered optical disk by SuperResolution (PSR) has been realized in read-only optical disks using phase-change materials. In the front ap erture detection (FAD) method for PSR, the prerecorded signal is read out only from the high reflective crescent-shaped area in the light sp ot, because the reflectance of the heated area is too low. A C/N of 51 dB for a mark length of 0.3 mum has been obtained for the PSR disk.