| Project/Area Number |
23K23191
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| Project/Area Number (Other) |
22H01923 (2022-2023)
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Multi-year Fund (2024)
Single-year Grants (2022-2023) |
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| Section | 一般 |
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| Review Section |
Basic Section 28050:Nano/micro-systems-related
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| Research Institution | Okinawa Institute of Science and Technology Graduate University (2024)
Hokkaido University (2022-2023) |
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Principal Investigator |
Pin Christophe 沖縄科学技術大学院大学, 量子技術のための光・物質相互作用ユニット, スタッフサイエンティスト (50793767)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Project Status |
Granted (Fiscal Year 2024)
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| Budget Amount *help |
¥14,950,000 (Direct Cost: ¥11,500,000、Indirect Cost: ¥3,450,000)
Fiscal Year 2024: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2023: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2022: ¥10,400,000 (Direct Cost: ¥8,000,000、Indirect Cost: ¥2,400,000)
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| Keywords | plasmonics / nanogap / chirality / enantioselectivity / hot electron |
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| Outline of Research at the Start |
The light-induced growth of gold nanoparticles is investigated to fabricate gold nanostructures with a twisted nanogap. The purpose of this project is the study of the interaction between such twisted gold nanostructures and molecules with twisted shapes. The goal is to induce and measure some asymmetry in this interaction depending on how twisted are the gold nanostructure and the molecules.
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| Outline of Annual Research Achievements |
An analytical model was developed to calculate the spatial distribution of the spin and orbital momentum carried by the electric field near the center of the nanogap of a plasmonic trimer nanoantenna excited either by a Gaussian laser beam or by an optical vortex laser beam. Theoretical analysis based on those results were used to discuss the experimental results obtained by my collaborator Dr. A.-C. Cheng. This work was published earlier this year in the scientific journal Small.
In parallel, numerical simulations were conducted to design plasmonic nanogap antennas that enable orbital angular momentum conversion between the incident light and the electric field in the vicinity of the nanogap. Especially, I designed both resonant and non-resonant antennas that enable the generation of optical nanovortex when irradiated by a circularly polarized plane wave. Those results have been presented at an international conference and some results have been submitted to the conference proceedings. A manuscript is under preparation to submit an article to a peer-reviewed scientific journal.
Based on those previous results, the chiral properties of the electric field in the vicinity of a plasmonic nanogap antenna have been investigated further. Especially, I numerically demonstrated the existence of nanoscale skyrmion patterns in the spin angular momentum texture of the electric field near the nanogap of plasmonic multimer antenna irradiated by a circularly polarized plane wave. This result may lead to new techniques to optically generate or control magnetic spin skyrmions.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
Due to some difficulties in the fabrication of gold nanostructures with a chiral nanogap and in the spectroscopic measurement of the fluorescence emission of chiral fluorophores, new directions are being investigated to explore chiral light-matter interactions using plasmonic nanogap antennas. Some results about the spin and orbital angular momentum of the nanogap electric field have been published, and another research article is under preparation to report on the design of plasmonic multimer antennas that enable the generation of optical nanovortex when irradiated by a circularly polarized plane wave.
Due to my recent move from Hokkaido University to the Okinawa Institute of Science and Technology, a new experimental setup is currently under construction.
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| Strategy for Future Research Activity |
Further experiments will be performed to investigate the fabrication of gold nanostructures with a chiral nanogap on a silicon substrate. Plasmonic nanogap antenna that enable the generation of optical nanovortex when irradiated by a circularly polarized plane wave will be also fabricated and, if possible, characterized by near-field optical microscopy technique. However, during the upcoming year, the fabrication of gold nanostructures by electron-beam lithography may require further usage of the cleanroom facility of the Research Institute for Electronic Science in Hokkaido University.
Spectroscopic measurements of the fluorescence properties of chiral fluorophores will be also further investigated.
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