| 摘要 |
PURPOSE:To reduce the size and weight of a pickup for photomagnetic medium and to make excellent the S/N of a signal to be detected. CONSTITUTION:A laser beam emitted by a semiconductor laser 15 and propagated on an optical waveguide 5 is collected on a photomagnetic disk 10 via an FGC 29 and a light collecting lens. A hologram optical element 43 diffracting the returning light from the photomagnetic disk is provided on the optical waveguide 5, and light detectors 20a to 20d detecting zero-order light and light detectors 22 to 25 detecting + or - first-order light on a substrate 1, respectively, are formed. |
