1991 Fiscal Year Final Research Report Summary
Investigation of Inhomogeneous Broadening of Optical Spectra of Localized Centers in Solids by Monochromatic-Light-Induced Fluorescence
| Project/Area Number |
02452039
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | Osaka University |
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Principal Investigator |
KUSHIDA Takashi Osaka Univ. Dept. of Physics Professor, 理学部, 教授 (00013516)
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| Co-Investigator(Kenkyū-buntansha) |
KANEMATSU Yasuo Osaka Univ. Dept. of Physics Research Associate, 理学部, 助手 (00211855)
KURITA Atusi Osaka Univ. Dept. of Physics Research Associate, 理学部, 助手 (70170082)
KIMURA Masahiro Osaka Univ. Dept. of Physics Research Associate, 理学部, 助手 (40028238)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Laser-induced Fluorescence / Inhomogeneous Broadening / Fluorescence Line-narrowing / Resonance Fluorescence / Noncrystalline Solids / Dye Molecules / Eu^<3+>Ion |
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| Research Abstract |
When the inhomogeneous broadening is significant in the optical spectra, such as in the case or localized electrons in glasses and polymers, it is possible to obtain detailed information only after the elimination of the effect of this inhomogeneous broadening. We have studied a method to eliminate inhomogeneous broadening in optical spectra by observing fluorescence from the sample which is excited by monochromatic light. Especially, it has been aimed to apply this site-selective fluorescence method to dye molecules in condensed matter, in which the discrimination between the scattered exciting light and fluorescence is difficult because of the short fluorescence decay time. We have shown that this is possible by combining ultra-short optical pulses from a cw mode-locked laser and a time-correlated single-photon counting method. In fact, we have succeeded, for the first time, in the d etermination of the site-selected fluorescence spectrum including the narrow resonance line in dye mo
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lecules in polymers and chromophores in proteins. Much information on the homogeneous and inhomogeneous spectra of impurity molecules in disordered systems, such as the site-energy distribution and single-site fluorescence spectra, has been obtained using this method.
Detailed analysis of the laser-induced fluorescence experiments in Eu^<3+>-doped materials has also been performed. It has been shown that we can determine various transition mechanisms as well as the distribution of the crystal-field parameters acting on the rare earth ion from the site-selected fluorescence characteristics. It has also been confirmed that all the data including the spectral shape of the laser-induced fluorescence and its dependence on the excitation wave-length are understood consistently by basing on the wave functions of the Eu^<3+> ion. The laser-induced fluorescence spectra in Eu^<3+>-doped glasses and polymers have been compared with the experiments of the applied pressure in Eu^<3+>-doped crystals, and the effectiveness of the site-selective fluorescence method has been established. Less
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