Optical pickup apparatus and a hologram element used for same

An optical pickup apparatus comprising:

• a light emitting means for emitting light beams;
• an optical scanning means for scanning a recording medium with said light beams;
• a light focusing means for focusing said light beams on said recording medium;
• an optical detector for detecting the light beams reflected from said recording medium;
• and
• a first optical system for detecting the light beams reflected from said recording medium to said optical detector;
• wherein said optical scanning means comprises an optical diffraction means for diffracting the light beams emitted from said light emitting means and a control means for controlling the rotation of said optical diffraction means, said optical diffraction means including a hologram element comprising a light-transmitting substrate having a first surface with a first hologram formed thereon and a second surface with a second hologram formed thereon, wherein the first hologram has a grating of approximately straight lines, and the second hologram has a grating of concentric arcs having a center on an imaginary straight line, said imaginary straight line being perpendicular to the straight lines of the grating of the first hologram and including a center of the rotation of said hologram element.