Schörner Christian, Lippitz Markus
Experimental Physics III, University of Bayreuth, Bayreuth, Germany.
J Chem Phys. 2021 Dec 21;155(23):234202. doi: 10.1063/5.0074387.
Plasmonic nanoparticles in close vicinity to a metal surface confine light to nanoscale volumes within the insulating gap. With gap sizes in the range of a few nanometers or below, atomic-scale dynamical phenomena within the nanogap come into reach. However, at these tiny scales, an ultra-smooth material is a crucial requirement. Here, we demonstrate large-scale (50 μm) single-crystalline silver flakes with a truly atomically smooth surface, which are an ideal platform for vertically assembled silver plasmonic nanoresonators. We investigate crystalline silver nanowires in a sub-2 nm separation to the silver surface and observe narrow plasmonic resonances with a quality factor Q of about 20. We propose a concept toward the observation of the spectral diffusion of the lowest-frequency cavity plasmon resonance and present first measurements. Our study demonstrates the benefit of using purely crystalline silver for plasmonic nanoparticle-on-mirror resonators and further paves the way toward the observation of dynamic phenomena within a nanoscale gap.
紧邻金属表面的等离激元纳米粒子将光限制在绝缘间隙内的纳米尺度体积中。当间隙尺寸在几纳米或更小范围内时，纳米间隙内的原子尺度动力学现象就能够被研究。然而，在这些微小尺度下，超光滑材料是一项关键要求。在此，我们展示了具有真正原子级光滑表面的大规模（50μm）单晶银薄片，它们是垂直组装银等离激元纳米谐振器的理想平台。我们研究了与银表面间距小于2nm的结晶银纳米线，并观察到品质因数Q约为20的窄等离激元共振。我们提出了一个用于观察最低频率腔等离激元共振的光谱扩散的概念，并展示了首次测量结果。我们的研究证明了使用纯结晶银制作镜上等离激元纳米粒子谐振器的优势，并进一步为观察纳米尺度间隙内的动力学现象铺平了道路。
