| Project/Area Number |
12555234
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
工業分析化学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
FUJINAMI Masanori The University of Tokyo, Graduate School of Frontier Science, Associate Professor, 大学院・新領域創成科学研究科, 助教授 (50311436)
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| Co-Investigator(Kenkyū-buntansha) |
KATAYAMA Kenji The University of Tokyo, Graduate School of Frontier Science, Research Associate, 大学院・新領域創成科学研究科, 助手 (00313007)
SAWADA Tsuguo The University of Tokyo, Graduate School of Frontier Science, Professor, 大学院・新領域創成科学研究科, 教授 (90011105)
由井 宏治 東京大学, 大学院・新領域創成科学研究科, 助手 (20313017)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥13,200,000 (Direct Cost: ¥13,200,000)
Fiscal Year 2001: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2000: ¥9,200,000 (Direct Cost: ¥9,200,000)
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| Keywords | near-field / optical microscope / optical fiber / photothermal / dye particle / inverted optical microscope / scanning near-field optical microscope |
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| Research Abstract |
Much attention to a scanning near-field optical microscope(SNOM) has been paid in this decade by overcoming the diffraction limit to reach nanometeric size. Photothermal spectroscopy is highly sensitive and versatile technique, which is applicable for non-fluorescent molecules, so that photothermal (PT) -SNOM can be used as a promising tool in thin-film analysis. In this study we have developed the PT-SNOM and investigated the performance. The molecules are excited by the evanescent wave emitted from the small aperture of the optical fiber probe and the probe laser beam for detection of the induced refractive index is coaxially introduced with the excited beam.
The PT-SNOM was based on inverted optical microscope. A He-Cd laser was used as an excitation source at 422 nm, while a He-Ne laser as a probe beam at 633 nm. Both the laser beams were coaxially introduced into a metal-coated optical fiber probe with an apex diameter of around 100 nm. A shear-force feedback kept the fiber probe-sample distance of 10 nm. The transmitted probe beam was collected by the objective lens and passed through a holographic notch filter to remove excitation light of 422 nm.
The thin film of gold (80 nm) on a glass is used for the sample and the photothermal signal image can be obtained in PT-SNOM. The irradiation either of excitation laser or of probe laser does not results in any signals. This is the first evidence of detection of photothermal signal and image in SNOM. The space resolution is estimated to be 1 μm. Fast modulation frequency for excitation laser and Short time constant in lock-in amplifier are required in order to get the photothermal signal image, so the improvement of S/N ratio is in progress.
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