2001 Fiscal Year Final Research Report Summary
Terahertz Radiation from High-Tc Superconductors and Related Materials
| Project/Area Number |
11231202
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
HANGYO Masanori Research Center for Superconductor Photonics, Osaka University, Professor, 超伝導フォトニクス研究センター, 教授 (10144429)
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| Project Period (FY) |
1999 – 2002
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| Keywords | terahertz wave / high-Tc superconductor / ultrashort optical pulse / supercurrent mapping / terahertz time domain spectroscopy / terahertz imaging / semiconductor surface / photonic crystal |
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| Research Abstract |
The purposes of the project are 1. to clarify the whole properties of terahertz (THz) radiation from high-Tc superconductors and 2. to apply THz waves to characterization of various materials including high-Tc superconductors. The obtained results are
1. High-Tc superconductor YBCO THz emitting devices with various types of antenna structures have been fabricated and their emission properties are investigated. It is found that the log-periodic type device is most efficient and the intensity reached 10 μW with 100 mW excitation intensity.
2. Apparatus for visualizing the supercurrent flow using THz radiation is constructed and applied to investigate the supercurrent distribution under various conditions.
3. THz radiation from semiconductor surfaces and polymers is measured. It is found that the waveform radiated from semi-insulating InP chenges its sign at 〜 140 K and the intensity is strongly enhanced at 〜 500 K for semi-insulating GaAs. The results are explained by the drift-diffusion model for photoexcited carriers.
4. Various types of THz time domain spectroscopic (THz-TDS) systems are constructed and applied to characterizing various materials.
5. By applying THz-TDS system to characterizing photonic crystals, nearly complete agreement between experiment and theory is obtained for 2-dimensional dielectric array photonic crystal.
6. A THz imaging system for general use is connstructed and applied to imaging metallic objects and photocarriers in semiconductors.
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