Optical pick-up apparatus and semiconductor laser apparatus

An optical pick-up apparatus comprising:

• a light source for emitting laser light in two wavebands;
• a light-receiving element for receiving laser light which is emitted from the light source and is reflected by an optical recording medium;
• and
• a grating having polarization characteristics between the light source and the optical recording medium by which the laser light emitted from the light source and being incident is transmitted without diffraction when a polarization direction for the laser light is equal to a predetermined first polarization direction and also by which the laser light emitted from the light source and being incident is diffracted when a polarization direction for the laser light is equal to a predetermined second polarization direction,
• the optical pick-up apparatus performing at least one of processes for reading information of the optical recording medium and recording information on the optical recording medium by irradiating the optical recording medium by the laser light emitted from the light source on the optical recording medium, and
• the polarization directions of the laser lights in the two wavebands being orthogonal with each other on a position on which the laser light is incident on the diffraction grating.