| 摘要 |
PURPOSE:To stabilize a laser beam source and to improve a C/N by providing a polarizing means which eliminates S polarization to be returned to the laser beam source of reflected light in an irradiation optical system which projects a laser beam in spot shape on a magneto-optical disk. CONSTITUTION:In the reflected light by the magneto-optical disk D, its polarizing plane is rotated in a direction of magnetization by a light spot, and the light is made incident on a first polarizing beam splitter 4 after passing an objective lens 6 and a mirror 5. An S polarized component in a direction of X out of incident reflected light on the first polarizing beam splitter 4 is made incident on a polarizing filter 21 after around 1% of it transmits the polarizing beam splitter 4, however, since the polarizing filter 21 shields the S polarized component in the direction of X, no S polarized component in the direction of X of the reflected light is made incident on the laser beam source 1. Thereby, the fluctuation of the S polarization of the laser beam due to the fluctuation of the light emitting component of the laser beam source 1 itself can be eliminated, then, the C/N can be improved. |
