| 摘要 |
PURPOSE:To miniaturize a constitution, by using two pairs of grating elements which diffract mainly polarized components intersecting orthogonally with each other respectively. CONSTITUTION:A laser beam from a semiconductor laser 1 is projected on a recording medium 4 after passing the two pairs of grating elements 2a and 2b provided between the laser 1 and a convergence lens 3 and being changed to a micro spot. And reflected light becomes two beams of diffracted light by the elements 2a and 2b in which gratings with different cycles diffracting the polarized components intersecting orthogonally with each other are formed, and are made incident on corresponding bi-sected type optical detector 5 and quarter-sected type optical detector 6 respectively. In such a way, it is possible to eliminate and analyzer or a polarizing beam splitter in a system to detect the rotation of a polarizing plane and to simplify and miniaturize the constitution of a head device for magneto-optics.
|
