2014 Fiscal Year Research-status Report
Revealing the near-field properties of coupled plasmonic systems by photoemission electron microscopy
| Project/Area Number |
26870014
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| Research Institution | Hokkaido University |
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Principal Investigator |
孫 泉 北海道大学, 創成研究機構, 特任助教 (90727463)
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| Project Period (FY) |
2014-04-01 – 2016-03-31
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| Keywords | Surface plasmon / Plasmaon coupling / Near field / Dephasing / PEEM |
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| Outline of Annual Research Achievements |
In 2014,we have investigated the near-field properties of two coupled plasmonic systems using photoemission electron microscopy. For the first plasmonic system, gold nanochain structures, we found the evolution of the near-field surface plasmon peak wavelengths with the chain length and gap distance has the same tendency as that observed from far field, providing the direct proof of the near-field coupling in the nanochains. As the result of near-field coupling, the energy transport along the nanochains was also demonstrated upon the oblique light irradiation. The role of the near-field coupling and retardation effect induced subradiant plasmon modes in the energy transport has been elucidated. For the second plasmonic system, dolmen structures, we observed the Fano resonance directly from the near field. The near-field mapping of different plasmon modes on the dolmen structures have been formed. The results provide abundant information about the near-field properties of plasmon coupling on complex plasmonic systems and will help to understand the nature of the plasmon coupling.
We have also explored the near-field properties of both fundamental and high order localized surface plasmon resonances. For simple gold nanoblock structures, we demonstrated the selective excitation of dipole and quadrupole LSPR modes. More importantly, the dynamics (dephasing) of the surface plasmon resoances could be studied by time-resolved PEEM. In particular, we experimentally proved that the subradiant quadrupole mode have longer dephasing time than the superradiant dipole mode.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The research project has progressed smoothly as we planned. We have investigated plasmonic systems，in which plasmon coupling is involved，by photoemission electron microscopy. Some significant results have been obtained. Two relevant manuscripts have already been prepared and will be ready for submission soon.
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| Strategy for Future Research Activity |
In 2015, we will continue the studies of Dolmen structures and further understand the plasmon coupling on this plasmonic system.Especially, we will focus on how the bright mode interacts with the dark mode from the viewpoint of near field.We will also consider investigating the plasmon coupling in simple T-type nanostructures using PEEM.Furthermore, we will compare the dephasing behavior of the couple plasmon modes with the single plasmon modes (dipole or higher order resonances). We expect we will find some common properties of the coupled plasmon modes in near field and predict some applications of plasmon coupling.
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| Causes of Carryover |
Some optics parts purchased last fiscal year were delivered slightly later than scheduled. Also, the proposed publication fee for the last fiscal year has not been used. Although we have prepared two manuscripts related to this project, we are still improving the manuscripts.
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| Expenditure Plan for Carryover Budget |
We will use the incurring amount in the next fiscal year for some optics parts, publication fee and other relevant expense (traveling fee).
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Research Products
(10 results)
