| 摘要 |
PURPOSE:To obtain an optical head for photomagnetic memory with a high detecting sensivity by bringing a plane of polarization for the linearly polarized light and that for the analyzer from the cross and parallel Nicol conditions to the setting condition of a fixed angle for reproducing operation. CONSTITUTION:The light intensity (f) given the angle theta between the polarization direction of the polarizer 1 and that of the analyzer 2 is presented by an equa tion. For reproduction of recording bits in optical/magnetic memory, reflected light has a rotation in the plane of polarization at most 1-2 deg. depending on the direction of magnetization, and therefore a change in polarization of record ing bits as shown with the broken line. This change is detected as the change in light intensity by the analyzer, and adjustment and setting of the directions of the polarization of the polarizer 1 and the analyzer 2 should preferably be made so that this change is maximized. Further, the detecting sensivity for the rotation angle of the plane of reflected light can be maximized by turn ing the polarizer 1 and the analyzer 2 45 deg. from the cross or parallel Nicol condition. The angle should be within 45 deg.+ or -18.5 deg. so that the sensitivity error is smaller than 20%.
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