| Project/Area Number |
17540375
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
原子・分子・量子エレクトロニクス・プラズマ
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| Research Institution | Meiji University |
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Principal Investigator |
ODASHIMA Hitoshi Meiji University, Department of Physics, Professor (50233557)
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| Co-Investigator(Kenkyū-buntansha) |
TACHIKAWA Maki Meiji University, Department of Physics, Professor (60201612)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,650,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥150,000)
Fiscal Year 2007: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | terahertz / far-infrared / difference frequency / molecular spectroscopy / 原子・分子物理 / 光源技術 / 差周波発生 |
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| Research Abstract |
A tunable coherent terahertz radiation was obtained by difference frequency generation of two near infrared semiconductor lasers(850nm) with a GaAs photomixer Using this radiation, we have developed a spectrometer to observe terahertz spectra of various materials.
(1) Generation of Terahertz Radiation : Various characteristics of a photomixer were measured to find out the best condition to generate a terahertz radiation : Bias characteristics, frequency characteristics, and incident-power dependence.
(2) Construction of a spectrometer : We have constructed a spectrometer using an obtained terahertz radiation and made performance evaluation of it by observing spectra of water and methanol.
(3) Improvement in Resolution : The resolution of the spectrometer is limited by fluctuation of the laser frequency. The semiconductor laser was locked to a saturated absorption from D_2 line of Cs atoms to improve resolution of the spectrometer.
(4) Accurate Frequency Measurement : The terahertz frequency is determined from the difference between two laser frequencies measured with a wavemeter, and therefore its accuracy is limited to〜30 MHz. For more accurate measurement, we performed a preliminary experiment of frequency measurement with an optical frequency comb.
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