Abstract: A high density compact disc having tracks for recording large amounts of information reproducible for a long interval of time is disclosed. In order to increase the track density, a recording surface on a substrate is divided into grooves and lands to thereby form tracks, and pits representing information signals are arranged in both the grooves and the lands. Here, the groove is formed at an optimized predetermined depth, depending on the wavelength of light used to read the information recorded on the disc and the refractive index of a disc substrate, to thereby reduce crosstalk caused by pits of an adjacent groove or land during reproduction. Accordingly, the present invention is effective in enhancing the practicality of the compact disc as a medium for preserving large amounts of information.

Abstract: A high-density magneto-optical disk apparatus is provided for removing a cross talk between signals of an adjacent track with respect to a track to be reproduced during reproduction of a signal recorded on a magneto-optical disk. In the case that a track pitch is narrowed for high-density recording in a magneto-optical disk apparatus, a cross talk occurs between a track to be detected and an adjacent track thereto. The magneto-optical disk apparatus uses a phase modulation optical element to form an optical spot having a linear polarizing state in a reproduction track and a circular polarizing state in an adjacent track, on the recording surface of the magneto-optical disk. Accordingly, although a track pitch is considerably reduced compared with the optical spot, a signal interference effect, that is, a cross talk between tracks can be removed to thereby provide a high-density magneto-optical disk.