High Density Magneto-Optical Recording with a Second-Harmonic Generation Green Laser

Abstract

Tripled areal density optical recording was realized with the combination of a high power laser-diode pumped intracavity frequency-doubled Nd:YAG laser (SHG green laser), a low noise GdFeCo/TbFeCo double-layered magneto-optical (MO) disk, and high sensitivity photodetectors optimized for the wavelength of the light source. A high carrier-to-noise (C/N) ratio of more than 48 dB and a bit error rate of less than 3×10-6 by (2, 7) run-length-limited (RLL) mark position recording was obtained at a mark length of 0.45 µm (0.6 µm/bit) for a disk with a 0.9 µm track pitch.

Effect of sputtering condition on dynamic characteristics and microstructures of magneto-optical 5.25 in. SiN/TbFeCo/SiN/Al disks for 532 nm recording media

“…Recently, a comparably increased information storage capacity of the magnetic recording media due to persistent research and development motivated the use of short wavelength lasers for writing and reading in the magneto-optical media. [2][3][4] However, the readout carrier-to-noise ratio ͑CNR͒ is known to decrease due to a deteriorated Kerr rotation angle at the short wavelengths. It has been reported that the static magnetic properties of Tb-Fe-Co thin films are influenced to a large extent by the sputtering parameters of the magneto-optical layer.…”