| Project/Area Number |
13480128
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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 | 一般 |
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| Research Field |
プラズマ理工学
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| Research Institution | Osaka University |
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Principal Investigator |
MIYANAGA Noriaki Osaka University, Institute of Laser Engineering, Professor, レーザー核融合研究センター, 教授 (80135756)
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| Co-Investigator(Kenkyū-buntansha) |
TSUBAKIMOTO Koji Osaka University, Institute of Laster Engineering, Research Associate, レーザー核融合研究センター, 助手 (90270579)
KODAMA Ryosuke Osaka University, Institute of Laster Engineering, Associate Professor, レーザー核融合研究センター, 助教授 (80211902)
SAKABE Shuji Osaka University, Faculty of Engineering, Associate Professor, 工学研究科, 助教授 (50153903)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥14,400,000 (Direct Cost: ¥14,400,000)
Fiscal Year 2002: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2001: ¥10,200,000 (Direct Cost: ¥10,200,000)
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| Keywords | ultra-short-pulse laser / plasma interaction / Laguerre-Gasussian beam / optical vortex / axially symmetric polarization / ultra-fast light probe / phase element / longitudinal electric field / 軸対象偏光 / ピコ秒動画 / 電子加速 / 液晶旋光素子 |
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| Research Abstract |
1) Generation of ultra-short-pulse optical vortex using spiral phase shifter: A spiral phase shifter was fabricated by coating a 16-steppatterned SiO* onto a glass substrate. The phase distribution was in good agreement with that predicted by the computed hologram, and then an optical vortex (Laguerre-Gaussian beam with a topological charge of 1) was successfully obtained.
2) Imaging with sub-ps time resolution: A 130-fs ultra-short Ti: sapphire laser pulse was frequency doubled. Then optical probe system was constructed using this UV pulse for measuring short-life plasmas by shadowgraphy and interferometer techniques. The propagation of ultra-short-pulse laser light and the dynamics of plasma formation were observed using this probing system, and their dependence on laser phase/polarization distributions was studied.
3) Generation of longitudinal electric field from laser: A linearly polarized light was converted to axially symmetric polarization (radial polarization and azimuthal polarization) with an efficiency greater than 90% using a polarization distributed plate based on an optical rotatory of liquid crystal. A longitudinal electric field of 10*V/m was observed near a focal spot of 0.45-MW radially polarized Nd: YAG laser. Thus 0.1TV/m can be realized using a TW class high power laser.
4) Particle acceleration with optical vortex and radial polarization: Ti: sapphire laser pulse of 0.5-1TW was focused onto a solid or gaseous target. The measured electron spectra suggest that these special laser modes can enhance the amount of forward accelerated electrons especially in high energy component.
5) Particle simulation: A particle simulation code has been newly developed for the analysis of the effects caused by the phase/polarization distribution. This code showed that the substantial increase of high-energy electrons for combining the Laguerre-Gaussian beam with circular polarization.
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