| 研究課題/領域番号 |
22K03493
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| 研究種目 |
基盤研究(C)
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| 配分区分 | 基金 |
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| 応募区分 | 一般 |
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| 審査区分 |
小区分13020:半導体、光物性および原子物理関連
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| 研究機関 | 筑波大学 |
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研究代表者 |
トン ショウミン 筑波大学, 計算科学研究センター, 准教授 (80422210)
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| 研究期間 (年度) |
2022-04-01 – 2026-03-31
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| 研究課題ステータス |
交付 (2023年度)
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| 配分額 *注記 |
4,160千円 (直接経費: 3,200千円、間接経費: 960千円)
2025年度: 520千円 (直接経費: 400千円、間接経費: 120千円)
2024年度: 390千円 (直接経費: 300千円、間接経費: 90千円)
2023年度: 520千円 (直接経費: 400千円、間接経費: 120千円)
2022年度: 2,730千円 (直接経費: 2,100千円、間接経費: 630千円)
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| キーワード | Atomic excitation / Intense laser / metastable states / elliptical polarization / highly charged ions / Elliptical polarization |
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| 研究開始時の研究の概要 |
Different from atomic ionization, atomic excitation depends on more details of the atomic structure, like our fingerprint and it must be studied case by case or element by element. Such an understanding may result in a new development on steering coherent excited states by tuning the relative phase of the light source, the time-delay between the pump and probe lasers. Most of the excited states will be de-excited to a metastable gas phase, which can be used for atom trap trace analysis.
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| 研究実績の概要 |
This year, we searched the efficient way to produce metastable Ar atoms using a two-color laser system. Since the parameter space is too large, we developed a search algorithm based on the Genetic Algorithm. Using this method, we hope to find an efficient way to produce metastable Ar atoms, which can be used for Atom Trap Trace Analysis.
We collaborated with the experiment group in RIKEN to analyze the decay dynamics of muonic Ar atomic ion measured in the experiment. After extensive discussions, we found that the initial captured states are much higher than we thought. The work was presented at the XXXIII International Conference on Photonic, Electronic, and Atomic Collisions as an invited talk.
Meanwhile, we theoretically studied the high-order harmonic generation (HHG) from Ar gas targets in an intense laser pulse. We calculated the macroscopic HHG energy distribution and divergence. We also discussed the dependency of the macroscopic HHG on the gas pressure and gas jet position. This is the first work to calculate the macroscopic HHG from the first principle. The results were published in Physical Review A.
We also systematically studied the interference effect on the abnormal polarization from dielectronic recombination and we found that the Breit interaction is not important even for very high-Z ions. For low-Z ions, the configuration interaction of the DR states affects the polarization greatly while for high-Z ions, the configuration interaction of the ground state of Be-like ions plays an important role. The results were published in Physical Review A.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
In this proposal, our goal is to understand and control the atomic excitation in a strong field. We had preliminary results: we may get up to 10% metastable Ar atoms with optimized laser parameters. Starting from April 2023, our joint research was funded by the Australian Research Council under the title of “Novel source of excited metastable atoms for Atom Trap Trace Analysis” by Discovery Project Grand ID: DP23010153. This support will speed up the present research project.
We also collaborated with an experiment group in RIKEN to study the energy structure and dynamics of muonic Ar atoms. We are working to write the paper.
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| 今後の研究の推進方策 |
(a) We will focus our work on the efficient production of metastable Ar atoms, and search how to enhance the production of metastable Ar atoms using Genetic Algorithm. Such laser parameters will be used in experiments performed at Griffith University. By the collaboration between theory and experiment, we hope to find a better way to efficiently produce metastable Ar atoms, which can be further used in Atom Trap Trace Analysis for ocean current studies.
(b) Recently, we also started to work on doubly excited states of He in a strong laser field and collaborated with an experiment group at Max Planck Institute for Nuclear Physics. By such a collaboration, we want to understand the dynamics of laser-assisted photoexcitation processes.
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