| 摘要 |
Disclosed is an optical head, which has: a light-generating means which emits linearly polarized light; a lens which converges the light emitted from the light-generating means on a medium; a light-detecting means which receives the light reflected on the medium; a quarter-wave plate which is disposed between the light-generating means and the lens and rotates by pi /2 radian a polarization direction of the linearly polarized light when going and returning through the quarter-wave plate; a polarizing diffractive element which is disposed between the light-generating means and the quarter-wave plate, the polarizing diffractive element transmitting the light travelling from the light-generating means to the quarter-wave plate and diffracting the light travelling from the quarter-wave plate to the light-generating means by using a difference in polarization direction; and a polarizing beam splitter which is disposed among the light-generating means, the light-detecting means and the polarizing diffractive element, the polarizing beam splitter directing the light from the light-generating means to the polarizing diffractive element and directing the light from the polarizing diffractive element to the light-detecting means by using a difference in polarization direction; wherein the light-detecting means receives the light diffracted by the polarizing diffractive element and the light transmitted through the polarizing diffractive element. <IMAGE> |
