| 摘要 |
PROBLEM TO BE SOLVED: To obtain an apparatus which can achieve correct control even in a light-weight and compact structure, by arranging a volume hologram element between an optical recording medium to which a laser luminous flux is to be projected and a photodetecting means detecting a reflecting light from the recording medium, and recording information to the volume hologram element. SOLUTION: A laser light source 2, a collimator lens 4, a beam splitter 5, an objective lens 6, detectors 8, 9, etc., are arranged inside an optical pickup apparatus 1. A volume hologram element 7 is fixed at a predetermined position between the beam splitter 5 and each detector 8, 9 in a state in which information to be recorded to a hologram material is not recorded yet, When light waves of the same character as a first light wave enters the volume hologram element 7 recording interference fringes of the first light wave and a second light wave, the second light wave is reproduced because of the character. The volume hologram element 7 reproduces the light wave that is focused on the first detector for an optical disk 14 slightly shifted from a focal position. |
