| 摘要 |
PURPOSE:To obtain an extremely thin grating type optical polarizing plate by forming an optical diffraction grating of an ion exchange regions having periods on the main plane of a lithium niobate crystal plate and providing means for offsetting the phase change which the ordinary light component of the light waves transmitted through the diffraction grating receives in the ion exchange regions. CONSTITUTION:The lithium niobate crystal plate 1 has the proton ion exchange regions 2 which are periodically formed to provide the optical diffraction grating. Only the surface of, for example, the regions which are not subjected to the ion exchange are etched by as much as a desired depth in order to offset the phase change which the ordinary light component among the light waves to be transmitted through the diffraction grating receives in the ion exchange regions. The polarizing component oscillating in a y-axis direction, i.e., the ordinary light component passes the crystal plate 1 rectilinarly in the form of zero order light 4 when incident light 3 enters this polarizing plate. On the other hand, the extraordinary light component oscillating in the z-axis direction with the polarized incident light 3 oscillating in the y-axis direction emerges from the crystal plate 1 in the form of diffracted light 5 and 6. The thin and small-sized polarizing element is thereby obtd. |
