| 摘要 |
PURPOSE:To convert the polarizing state of a beam regardless of the wavelength of light by utilizing a phase change between a P wave and an S wave to be generated by reflecting the beam by using an optical means having a reflection face. CONSTITUTION:All the linearly polarized beams having various wave-lengths of semiconductor lasers 1-4 are converted to circularly polarized beams by a Fresnel prism 100 wile receiving the operation of reducing position error between P wave and the S wave to pi/2. On the other hand, the beam reflected by a medium 18 is also converted to the linearly polarized beam by introducing the similar phase difference by the prism 100. Since the beam passes through the prism 100 twice, the phase difference between the P wave and the S wave is turned to pi and therefore, the beam is reflected to the side by a polarized beam splitter 13 and guided into a hologram lens 19. Thus, the polarizing state can be converted regardless of the wavelength of the light and utilized for various pickup devices. |
