| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-performance optical head apparatus capable of stable signal detection using a semiconductor laser for two wavelengths. <P>SOLUTION: A diffraction device for two wavelengths is fabricated which includes a diffraction grating 11B for transmitting incident light having a wavelength of λ<SB>1</SB>and diffracting incident light having a wavelength of λ<SB>2</SB>and a phase plate 11C for changing the polarized state of transmitted light having at least one of the two wavelengths λ<SB>1</SB>and λ<SB>2</SB>, the diffraction grating 11B and the phase plate 11C being integrated together. The diffraction device is mounted on the optical head apparatus. <P>COPYRIGHT: (C)2010,JPO&INPIT |
