To elucidate the effect of structural irregularity on propagation properties of optical waves in discontinuous magneto-optical media, theoretical analysis was carried out by employing random matrix technique and a model with one-dimensional quasirandom array structure. The analysis revealed that the effect of structural irregularity was so significant that the dispersion curves of optical waves varied considerably depending on the media structures. However, no matter how the medium structure varies irregularly, dispersion curves of waves always exist within the confines between those of the half (0...01...1) and the alternate (0101...01) structures. This fact suggests that the effect of structural irregularity becomes less significant when the discontinuous media have fine discrete structures, where the dispersion curves of the half and the alternate structures are very close.

To elucidate unique Faraday spectra observed in porous magnetic films, we theoretically analyzed the magneto-optical Faraday effect of discontinuous media with an ideal one-dimensional array structure. The media are constituted by magnetic materials (width DM) and air gaps (width DG) which are aligned interchangingly. Propagation properties of optical waves in the media, such as the dispersion characteristics and the polarization states, were explored circumstantially, and apparent Faraday rotation and ellipticity spectra of the discontinuous media were obtained. The analysis reveals that the apparent Faraday spectra of the media vary to a large extent from those of a continuous medium depending strongly on the media structures. The key factors which govern the magneto-optical effect of the discontinuous media are structural elements of DM and 2(DM+DG): The Faraday spectra are subject to change only when DM<λ (λ: the wavelength of optical wave in a vacuum). Then, the magneto-optical effect of the magnetic materials is related to mode conversion from TE to TM when 2(DM+DG)<λ. If DM<λ<2(DM+DG), the mode conversions of both directions from TM to TE and TE to TM are possible. The mode conversion dominates the apparent Faraday spectra of the media, causing the enhancement in the Faraday rotation and systematic shift of the spectra toward shorter and/or longer wavelength of the optical waves. These results explain very well the unique Faraday spectra of the porous films.

We have investigated about a control technique of oxygen contamination into the InN layers by simultaneous irradiation of Ga beam during RF-MOMBE growth using the combination of the TMIn and the RFplasma nitrogen sources. Red shifts of the band gap energy and the improvement of the electrical properties have been achieved by the Ga beam irradiation. The suppresssion mechanism of the oxygen contamination has been discussed from the experimental results of the InN growth by the RF-MOMBE with the Ga beam irradiation. The present results strongly indicate that the simultaneous irradiation of the Ga beam would be useful to suppress the oxygen contamination into the InN layers during the growth.

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Magneto-optical Faraday effect of cobalt nano-dusters oriented uniaxially in a transparent matrix was studied. The experimental results showed that the oriented films were good polarizing plates with very unique MO properties which varied depending on the geometry of film structures and the polarization of incident lights. Numerical analysis revealed that the MO properties originated in the mode conversion of lights from TE to TM, arising from the magnetic and optical uniaxial anisotropies.