High density recording by superresolution in an optical disk memory system

Abstract

High density optical disk recording using an optical superresolution technique is proposed. By setting a shading band in the center of the collimating beam, the focused spot size on the recording medium is reduced to 80% compared with that of a conventional optical recording. The readout signal degradation affected by the focused spot sidelobe on the recording medium is suppressed by spatially extracting the main lobe region from the reflected back beam using a slit on a reimaged plane. The linear recording density has been improved to 1.2 times as high as that for a conventional optical recording using a normal resolution optical head.