| 摘要 |
PURPOSE:To prevent the deterioration of a regenerated signal with a simple constitution by providing a beam splitter having a phase difference reverse to the phase difference of P and S polarizations generated at a total reflection mirror in an optical system to conduct reflected light to a photodetector. CONSTITUTION:The outgoing light from a semiconductor laser 1 is condensed through an integrated prism 20 onto a recording medium 6. A part of the reflected light of the medium 6 is reflected on the beam splitter in the prism 20, and inputted to the optical system for detecting polarization rotation. On the reflecting surface of the splitter, multilayer films to compensate for the phase difference of both the polarization are formed, the polarization plane of the reflected light compensated for the phase difference is rotated by 45 deg. at a 1/2 wavelength plate 7, and divided into P and S polarization at a polarization beam splitter 8. The reflected light is made incident on a photodetector 10 through a convergent lens 9, and the signal is regenerated by the output difference of the detector 10. Thus, the deterioration of the regenerated signal is prevented with a simple constitution. |
