Optical pickup, including a mirror for changing light polarization direction, and information reproducing apparatus having the same

An optical pickup for reading an information signal by emitting a light beam to an information recording surface of a recording medium having a recording track composed of information pits arranged for recording the information signal, comprising:

• a light source which emits the light beam having linear polarization;
• an optical system which guides the emitted light beam to the information recording surface and further guides light that is emitted from the information recording surface based on the guided light beam, to an optical path different from an optical path to the light source;
• and
• a light-receiving device which receives the light guided by the optical system from the information recording surface,
• wherein the optical system controls a polarization direction of the emitted light beam, with respect to a direction of the recording track, and
• wherein the optical system comprises a semitransparent semireflecting mirror which reflects the emitted light beam, guides the light beam to the information recording surface after changing the polarization direction upon reflection, transmits the light from the information recording surface, and guides the light to the light-receiving device of the optical pickup.