Optical pickup including polarization holographic optical element and photodetector

摘要

Disclosed is an optical pickup including a polarization holographic optical element (HOE) and a photodetector. The optical pickup includes a light source, an optical path changer, an objective lens, a polarization HOE, and a photodetector. The polarization HOE has a pattern designed to generate different astigmatisms in the left and right halves of the polarization HOE in a tangential direction and to divide plus and minus first-order beams in a radial direction. The photodetector includes a first light-receiving portion receiving a zero-order beam and second and third light-receiving portion that are disposed on either side of the first light-receiving portion in the tangential direction and respectively receive the plus and minus first-order beams.