HIGH-TRACK-DENSITY FLATTENED MAGNETOOPTICAL DISKS WITH LOW CROSSTALK

The carrier-to-noise ratio (CNR), crosstalk and noise levels have been investigated for flattened and semiflattened magnetooptical disks wit h narrow track pitches of 1.2 and 1.0-mu-m. The track pitch of the fla ttened and semiflattened disks can be reduced to less than the laser s pot size under the condition that the laser spots irradiated on the ad jacent recording regions overlap each other only on the spiral guiding band. The CNR of 48.3 dB and low crosstalk of less than -36 dB were a chieved for the track pitch of 1.2-mu-m when the domains of 0.76-mu-m length were recorded. Crosstalk of less than -30 dB was obtained for t he track pitch of 1.0-mu-m with the conventional optical head having a n objective lens of 0.53 NA and a 780-nm laser.