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arXiv · 1912.11020

Nonlocal effects in plasmonic metasurfaces with almost touching surfaces

Fan Yang·Emanuele Galiffi·Paloma Arroyo Huidobro·John Pendry
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Abstract

Geometrical singularities in plasmonic metasurfaces have recently been proposed for the enhancement of light-matter interactions, owing to their broadband light-harvesting properties and extreme plasmon confinement. However, the large plasmon momenta thus achieved lead to failure of local descriptions of the optical response of metals. Here we study a class of metasurfaces consisting of a periodic metal slab with a smooth modulation of its thickness. When the thinnest part shrinks, the two surfaces almost touch, forming a near-singular point. Using transformation optics, we show analytically how nonlocal effects, such as a blueshift of the resonance peaks and a reduced density of states, become important and cannot be ignored in this singular regime. The method developed in this paper is very general and can be used to model a variety of metasurfaces, providing valuable insight in the current context of ultra-thin plasmonic structures.

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Fan Yang, Emanuele Galiffi, Paloma Arroyo Huidobro, John Pendry. 2019-12-23. Nonlocal effects in plasmonic metasurfaces with almost touching surfaces. https://doi.org/10.1103/physrevb.101.075434

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