| 摘要 |
PURPOSE:To reduce the loss of light quantity and to improve the S/N of a reading signal by providing the Faraday rotation elements between a beam splitter and a recording medium and between a pair of beam splitters. CONSTITUTION:A beam splitter 38 leads the laser beam of a light source 32 to a photomagnetic recording medium 41 and also leads the reflected light of the medium 41 to a detector 44. A Faraday rotation element 39 having the polarizing direction turned by a prescribed angle is set between the medium 41 and the splitter 38. In addition, a light turning element 37 and a Faraday rotation element 36 having the polarizing direction turned by a desired angle are set between the splitter 38 and a splitter 35 which leads the reflected light sent toward the light source 32 by the splitter 38 to a detector 46. In such a constitution, an optical system is simplified with reduction of loss of the light quantity. Thus the S/N is improved for the reading signal of the medium 41. |
