Magneto-Optical Disk for Blue Lasers

Abstract

We propose a new disk structure for conventional TbFeCo disks, which is suitable for blue laser light sources, i.e., an additional thin metal layer adjacent to the TbFeCo layer. The metal layer effectively improved a thermal characteristic of the medium, which resulted in a high carrier level even in a relatively high readout power. Using the improved medium, high-density recording was demonstrated in a 407 nm laser and 0.60 numerical aperture (NA) lens system. Despite the decay of the Kerr effect and photocurrent compared to those in an MD DATA2 red system, the new medium achieved an acceptable jitter level at a density of only about 11% lower than that expected from the MTF scaling. This effect was also found to be effective for a red laser with an NA 0.85 lens.