Magneto-optic Head Using Substrate-mode Grating Pairs For Polarization And Leaky Beamsplitting

In a magneto-optic data storage system, polarization and leaky beamsplitting ele­ ments are required in the optical pickup head.¹ The polarization beamsplitting element is used to sense the rotation of the beam polarization reflected from the magneto-optic disc medium. The leaky beamsplitter in conjunction with a half-wave plate is used to enhance the differential signal level detected from the medium. Conventionally, bulk prisms are used as polarization and leaky beamsplitters. In our novel substrate-mode grating pair structure, both functions can be performed.