High-Density Magneto-Optical Disk Using Land/Groove Recording and Magnetically Induced Super-Resolution by Rear Aperture Detection

Abstract

Magnetically induced super-resolution (MSR) by rear aperture detection (RAD) is characterized by very low cross-talk and very high resolution due to the use of both front and rear masks within laser spot. We investigated the possibility of making high-density Magneto-optical disks that use RAD combined with land-groove recording with a 690-nm wavelength diode laser and a 0.55 NA objective lens. We achieved a bottom jitter of 8.4% in grooves and 9.5% on lands, and a recording power margin of ±16.5% in grooves and±15.5% on lands at an areal density of 3.69 Gbit/in², with a 0.70-μm track pitch and a 0.25-μm bit length. These obtained values are acceptable for a magneto-optical disk system with a capacity of 5 GB/120 mm or 2 GB/8 mm.