Optical pickup for high-density recording/reproducing

摘要

An optical pickup for high-density recording/reproducing, which can read the information recorded at a close interval to exceed the limit of a given cut-off frequency, includes an objective lens having divided portions for respectively transmitting a zero-order optical component and +/-1st-order diffracted components. To detect a signal for reproduction, a focusing lens is used for focusing the zero-order component and +/-1st-order diffracted components passing back through the objective lens so as to mutually interfere. Stable high-density optical recording/reproduction can be realized regardless of the numerical aperture of the objective lens and the optical wavelength.