Super-resolution optical head apparatus

摘要

A linearly polarized light beam emitted from a coherent light source reaches a polarizing phase plate and is thereby divided into a primary beam and a subsidiary beam having a polarized light component perpendicular to the polarized light component of the primary beam and a double-humped pattern, in which the center position coincides with the center position of the primary beam and the principal portion is equal in size to the principal portion of the primary beam. The primary beam and the subsidiary beam are focused onto an information storage surface of an optical disk and reflected therefrom, so that they are separated again through polarization separation and individually detected by first to third optical detectors. The output signals from the first to third optical detectors are calculated by a differential calculator and outputted therefrom.