| 摘要 |
PURPOSE:To reduce the eclipse loss and make aberrations difficult to generate, by synthesizing optical beams from two light sources different in wavelength through a polarizing beam splitter and a filter and separating the reflected light from an information recording medium. CONSTITUTION:Optical beams 6a and 7a having wavelengths lambda1 and lambda2 from light sources 6 and 7 are incident to a polarizing beam splitter 8. The optical beam 6a is incident to the beam splitter 8 as a P-polarized light and is transmitted through the beam splitter 8 and a lambda/4 plate 9 and is reflected by a BPF 10, which reflects the wavelength lambda1 and permits the wavelength lambda2 to transmit through, and is turned back and is reflected by the deflecting prism 8 and is incident to an information medium 4 through a lambda/4 plate 11 and a stop lens 3. A reflected light 6b is turned back and is transmitted through the polarizing prism 8. The optical beam 7a is transmitted as a P-polarized light through the beam splitter 8 and is incident to the information medium 4, and a reflected light 7b is reflected by the beam splitter 8 and is emitted through the BPF 10. Consequently, the eclipse loss is small, and aberrations are difficult to generate. |
