Method and apparatus for direct overwrite on magneto-optical recording media using circularly polarized microwaves

摘要

A method of and system for utilizing circularly polarized microwave radiation in order to provide for the direct overwriting of previously recorded data on a single-layer magneto-optical disk is disclosed in which a microwave source is used to generate a sinusoidal magnetic wave having a fixed magnitude and fixed frequency which is applied to a phase shift switch whose phase is shifted between right circular and left circular polarization states, depending upon each bit of binary data to be recorded. The output from the phase shift switch is fed to a microwave antenna which is utilized to radiate the right circular or left circular polarized microwave signal to a small area of the magnetic film utilized in a magneto-optical disk which is heated by a focused laser beam at the moment during which recording at that location is desired.