Polarization Considerations In Magnetooptical Recording

Reading of magnetooptically recorded data relies on the detection of light whose polarization state varies very slightly with the direction of magnetization of the sensitive layer of the disk. Because the change in polarization is so small, differential detection methods are used, and a number of features of the optical detection scheme can adversely affect the polarization and the signal levels. Among those features considered are the polarization of the laser itself, optical surfaces within the head, substrate birefringence, and optical feedback.