| 摘要 |
PURPOSE:To obtain a large S/N by separating a parallel luminous flux polarized linearly into the 1st and the 2nd luminous flux, and making the 1st luminous flux incident to a recording medium having magnetic information so as to interfere the reflected light having the rotation of polarized plane obtained with the 2nd luminuous flux. CONSTITUTION:The luminous flux 11a irradiated from a light source such as laser is a luminous flux polarized linearly in an azimuth by a polarizer 12 and further divided into the 1st luminous flux 11b and the 2nd luminous flux 11d by a beam splitter 13. The luminous flux 11b of the divided luminous flux transmits through a beam splitter 14, is collected by an objective lens 15 on the recording medium 23 on which the magnetic information is recorded and reflected. In this case, the polarized component going straight into the azimuth of polarization of the luminous flux 11b by the magnetooptic Kerr effect. The reflected light passes through the objective lens 15 again, is reflected on the beam splitter 14 and transmitted through a beam splitter 19 as a luminous flux 11c. On the other hand, the other luminous flux 11d divided by the beam splitter 13 is reflected by the beam splitter 19 through a reflection mirror 16, a 1/2 wavelength plate 17 and a phase plate 18, and mixed with the luminous flux 11c transmitted through the beam splitter 19. |
