ABE Masanori Tokyo Inst.of Tech., Dept.of Physical Electronics, Prof., 工学部, 教授 (70016624)
FUJII Toshitaka Tohoku Univ., of Tech., Dept.of Electrical & Electronic Engng., Prof., 工学部, 教授 (90023168)
ARAI Ken Ichi Tohoku Univ., Research Inst.of Electrical Communication, Prof., 教授 (40006268)
|Budget Amount *help
¥3,400,000 (Direct Cost : ¥3,400,000)
Fiscal Year 1998 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1997 : ¥2,700,000 (Direct Cost : ¥2,700,000)
(1) Enhancement of magneto-optical Faraday and Kerr effects due to localization of light
Theoretical calculations revealed that the enhancement of magneto-optical effect associated with the localization of light is caused by the slight difference in localization wavelengths of fight-hand and left-hand circular polarized lights that are eigenmodes of lights in a magnetic film with magnetization parallel to the propagation direction of light. The computational results can be also explained from the theory, whose results coincide with the numerical results completely.
Based on these results, multilayer films that support the strong localization of light were investigated. It was found that the films with microcavity structures can support the strong localization of light and, as a result, the films exhibit considerably large magneto-optical effects. The localization effect of light in the multilayer films closely relates to the localized mode in the one-dimensional photonic crystals, and th
e mechanism of the localization effect and the resultant magneto-optical effect of the one-dimensional photonic crystals composed of magnetic materials (magnetophotonic crystals) were discussed in detail.
(2) Fabrication of magneto-optical microcavities with Co, amorphous TbFe, or rare-earth iron garnet films, and their properties
Based on the above results, films with (SiO_2/SiN)k/Co/(SiN/SiO_2)^k, (SiO_2/SiN)^k/a-TbFe/(SiN/SiO_2)^k, (SiO_2/Ta_2O_5)^k/Bi : DyIG/(Ta2O5/SiO2) structures were fabricated by means of RF sputtering and their optical and magneto-optical properties were investigated. These films showed optical and magneto-optical properties that coincide the above theoretical results quantitatively very well. In particular, the films supporting the strong localization of light showed large magneto-optical Faraday or Kerr effects, whose rotation angles are approximately 100 times larger than those of conventional magnetic single-layer films. These results indicate that the use of the localization of light is effective for realizing various magneto-optical devices.
(3) Magnetophotonic crystals
The multilayer films investigated in this study can be regarded as one-dimensional photonic crystals with spin-dependent optical properties (magnetophotonic cyrstals). From this respect, relation between the above films and the one-dimensional dielectric photonic crystals was studied. As a result, it is concluded that, in the magnetophotonic crystals with ordered and/or disordered structures, magneto-optical effect can be enhanced by the use of localization of light, From these results, two- and three-dimensional magnetophotonic crystals become very attractive, though their fundamental properties are still unclear. Then, further studies on magnetophotonic crystals with higher dimensions are necessary. Less