| 摘要 |
PURPOSE:To simultaneously extract plural beams having different wavelengths from one light source by alternately forming a band-like magnetic domain having positive magnetism in the thickness direction of a Bi substituted garnet film and a band-like magnetic domain with negative polarity on the film. CONSTITUTION:The Bi substituted garnet film 13 made to grow by liquid phase growth and having a thickness gradient in the direction from one side to the other side of the film 13 is formed on the upper face of an optical garnet substrate 12 and the film 13 is constituted by alternately forming the band-like magnetic domain 13a having the positive magnetism in the thickness direction and the band-like magnetic domain 13b having negative magnetism. Directly polarized light 18 generated from the light source 15 and made incident from the side on an optical medium 14 through a capacitor lens 16 and a polarizer 17 is reflected by respective reflecting faces 14a-14c, vertically penetrated into the substrate 12 from its lower face and made incident upon the film 13 and diffracted light 19 through the magnetic domain 13a of the film 13 is projected through an analyser 20. Consequently, three kinds of diffracted beams having different wavelengths each other can be obtained from one light source 15.
|
