Suppression of Radiative Damping and Enhancement of Second Harmonic Generation in Bull’s Eye Nanoresonators
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- 作者：Jue-Min Yi ; Vladimir Smirnov ; Xianji Piao ; Jiho Hong ; Heiko Kollmann ; Martin Silies ; Wei Wang ; Petra Gro? ; Ralf Vogelgesang ; Namkyoo Park ; Christoph Lienau
- 刊名：ACS Nano
- 出版年：2016
- 出版时间：January 26, 2016
- 年：2016
- 卷：10
- 期：1
- 页码：475-483
- 全文大小：467K
- ISSN：1936-086X
文摘
We report a drastic increase of the damping time of plasmonic eigenmodes in resonant bull’s eye (BE) nanoresonators to more than 35 fs. This is achieved by tailoring the groove depth of the resonator and by coupling the confined plasmonic field in the aperture to an extended resonator mode such that spatial coherence is preserved over distances of more than 10 μm. Experimentally, this is demonstrated by probing the plasmon dynamics at the field level using broadband spectral interferometry. The nanoresonator allows us to efficiently concentrate the incident field inside the central aperture of the BE and to tailor its local optical nonlinearity by varying the aperture geometry. By replacing the central circular hole with an annular ring structure, we obtain 50-times higher second harmonic generation efficiency, allowing us to demonstrate the efficient concentration of long-lived plasmonic modes inside nanoapertures by interferometric frequency-resolved autocorrelation. Such a light concentration in a nanoresonator with high quality factor has high potential for sensing and coherent control of light-matter interactions on the nanoscale.