| 摘要 |
PROBLEM TO BE SOLVED: To cancel a cross talk noise incorporated in a main spot by generating a beam consisting of the main spot and a sub-spot orthogonally intersecting with each other in their polarizing directions, irradiating it and differential detecting reflection light from a recording medium. SOLUTION: A first polarizing beam 5a and a second polarizing beam 5b orthogonally intersecting with each other in their polarizing directions are formed for an outgoing beam from a semiconductor laser 1 by a composite 1/2 wavelength plate 4. The main spot 9a on a magneto-optical disk 8 surface converging the first polarizing beam 5a by a focus lens 7 is provided with a peak in its center, and since the second polarizing beam 5b is shifted by 180 deg. in left/right polarizing phases, the sub-spot 9b is provided with a bi-peak characteristic having a center of zero and two peaks in left/right. The reflection light from the magneto-optical disk 8 is converged by the lens 7 to be differential detected by a polarizing beam splitter 10, photo-detectors 11, 12 and a differential amplifier 13, and then, the cross talk noise from an adjacent track incorporated in a reflection signal from the main spot 9a is removed. |
