Optical pickup and optical information recording/reproducing device

摘要

An optical pickup and an optical information recording/reproducing device are provided, each of which is capable of forming a super-resolution spot to conduct micro-mark recording, and does not undergo signal degradation due to an increased sidelobe in a reproducing operation. A variable phase filter 3 having three regions 3a to 3c to produce a phase difference in a radial direction is used, to provide a phase difference of pi between the center region 3b and the side regions 3a and 3c in a recording operation, so that a super-resolution spot is formed on a recording layer of the optical disk 5. In a reproducing operation, a phase difference is nullified between the regions 3a to 3c of the variable phase filter 3, so that a normal light spot at a diffraction limit having a smaller sidelobe is formed. The variable phase filter 3 can be formed with a homogeneous-alignment liquid crystal element. <IMAGE> <IMAGE>