Shoichi Takasuka

Photodetector unit, and optical pickup, optical reproduction apparatus, and optical recording apparatus equipped with the same

Diffractive optical element that polarizes light and an optical pickup using the same

Optical device with diffraction grating having plural grating regions

Semiconductor laser device and optical pickup device using the same

Optical device, optical semiconductor device, and optical information processor comprising them

Optical pickup with improved optical properties

An optical pickup with improved optical properties, and a method for manufacturing the optical pickup

Optical element with diffraction grating, semiconductor device, and optical information recording device employing the same

Optical head device and optical recording and reproducing apparatus

Optical head device and optical recording and reproducing apparatus having lasers aligned in a tangential direction