Abstract text

An optical pickup includes: a light source that emits a light beam; an object lens that condenses the light beam on a target recording layer of an optical disk; a lens moving unit; a condensing lens; a hologram element that diffracts, in diffracting a reflected light beam and separating it into reflected zeroth-order and first-order light beams, parts of the reflected first-order light beam in a first direction and sets them as first and second beams, diffracts parts of the reflected first-order light beam in a second direction and sets them as third and fourth beams; and a photodetector that receives the first and second beams and the third and fourth beams and generates light reception signals, and receives interlayer stray light of a part of the light beam reflected by the other recording layers other than the target recording layer and generates a stray light reception signal.