| 摘要 |
PURPOSE:To make the magnetooptic conversion efficiency most suitable by giving a bias magnetic field vertically to a magnetic garnet film and using its magnetic domain in the magnetic bubble state or the single magnetic domain state. CONSTITUTION:A bias magnetic field HB is preliminarily made larger then a bubble extinguishing magnetic field to set the single magnetic domain state. Though a garnet film 3 is in the single magnetic domain state when the direction of a signal magnetic field hB from a medium 1 which is given to the film 3 through a high-permeability film 2 is equal to the direction of the magnetic field HB, the effective bias magnetic field is reduced to generate a bubble magnetic domain if said directions are opposite. When a linearly polarized optical beam whose diameter is approximately equal to that of a bubble 5 is irradiated and the magnetization stae is discriminated by the Farady effect, the direction of te angle of polarization is opposite throughout the irradiated area between the single magnetic domain state and the bubble state, and the magnetooptic conversion efficiency is maximized, and the signal reproducing efficiency is suitable in comparison with the case where the bias magnetic field HB is not given. |
