Polarizing diffraction grating and a magneto-optical head using the same

摘要

A diffraction grating having more than two kinds of mediums of a different refractive index, has a refractive index difference between the mediums dependent on an incident polarized light direction. In a sectional plane perpendicular to the direction along a grating pattern, the structure has a boundary line between the mediums periodic for the direction perpendicular to the grating pattern in a grating plane or periodic while enlarging or shrinking to the direction perpendicular to the direction along with the grating pattern in the grating plane and in a limited part of a period, the boundary line does not have a symmetrical plane perpendicular to both of the grating and the sectional plane. Accordingly, a polarized light beam status of ±nth order diffracted light beams becomes different and there is provided a diffraction grating capable of obtaining a generation signal of a magneto-optical recording medium from a difference of an optical amount of a light beam received.