Böckmann Hannes, Liu Shuyi, Müller Melanie, Hammud Adnan, Wolf Martin, Kumagai Takashi
JST-PRESTO , 4-1-8 Honcho , Kawaguchi , Saitama 332-0012 , Japan.
Nano Lett. 2019 Jun 12;19(6):3597-3602. doi: 10.1021/acs.nanolett.9b00558. Epub 2019 May 15.
Near-field manipulation in plasmonic nanocavities can provide various applications in nanoscale science and technology. In particular, a gap plasmon in a scanning tunneling microscope (STM) junction is of key interest to nanoscale imaging and spectroscopy. Here we show that spectral features of a plasmonic STM junction can be manipulated by nanofabrication of Au tips using focused ion beam. An exemplary Fabry-Pérot type resonator of surface plasmons is demonstrated by producing the tip with a single groove on its shaft. Scanning tunneling luminescence spectra of the Fabry-Pérot tips exhibit spectral modulation resulting from interference between localized and propagating surface plasmon modes. In addition, the quality factor of the plasmonic Fabry-Pérot interference can be improved by optimizing the overall tip shape. Our approach paves the way for near-field imaging and spectroscopy with a high degree of accuracy.
等离子体纳米腔中的近场操纵可在纳米科学与技术领域提供多种应用。特别是，扫描隧道显微镜（STM）结中的间隙等离子体激元对于纳米级成像和光谱学具有关键意义。在此，我们表明通过聚焦离子束对金尖端进行纳米加工，可以操纵等离子体STM结的光谱特性。通过在其轴上制造具有单个凹槽的尖端，展示了表面等离子体激元的典型法布里-珀罗型谐振器。法布里-珀罗尖端的扫描隧道发光光谱呈现出由局域表面等离子体激元模式与传播表面等离子体激元模式之间的干涉所导致的光谱调制。此外，通过优化整体尖端形状，可以提高等离子体法布里-珀罗干涉的品质因数。我们的方法为高精度的近场成像和光谱学铺平了道路。
