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.
High-Q plasmonic nanowire-on-mirror resonators by atomically smooth single-crystalline silver flakes
Note: This paper is part of the JCP Special Topic on The Ever-Expanding Optics of Single-Molecules and Nanoparticles.
Christian Schörner, Markus Lippitz; High-Q plasmonic nanowire-on-mirror resonators by atomically smooth single-crystalline silver flakes. J. Chem. Phys. 21 December 2021; 155 (23): 234202. https://doi.org/10.1063/5.0074387
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