| 摘要 |
PURPOSE:To obtain a recording pattern which is remarkable in a difference of light and shade, by comparing with a polarization component in a prescribed direction of a modulation luminous flux, increasing relatively a polarization component in the direction being vertical to said direction, and substantially expanding an angle of rotation of the modulation luminous flux. CONSTITUTION:An optical element 9 has such a quality as transmission and reflection factors are different depending on its polarized direction. In case when a luminous flux (b) which has passed through the optical element 9 is reflected by a vertical magnetic recording body 10, the polarized surface is rotated in accordance with a magnetizing direction of an area illuminated by the luminous flux due to a Kerr effect. When the transmission polarized direction of a photodetector 11 is placed vertically in a polarized direction -phi of a luminous flux (d), a luminous flux having its polarized direction in the -phi direction is cut off, only a diagonal shaped component against the transmitting direction of the photodetector 11 of the polarized luminous flux in the phi direction transmits the photodetector 11. |
