Spectral behavior of localized plasmon resonances in the near- and far-field regimes. Comment on The spectral shift between near- and far-field resonances of optical nano-antennas

TL;DR

This paper critiques a recent analysis of spectral shifts in plasmonic nano-antennas, clarifying that the previous interpretation was incomplete and emphasizing the need for additional physical concepts.

Contribution

It provides a critical commentary on prior work, highlighting missing concepts and offering clarifications on the spectral shift phenomenon in plasmonic resonances.

Findings

The spectral shift interpretation in prior work is incomplete.

Additional physical concepts are necessary for accurate understanding.

Clarifications improve the theoretical understanding of plasmonic resonances.

Abstract

In a recent paper by Menzel et al. (Opt. Exp. 22, 9971 (2014)), its authors analyze the spectral red-shift effect of plasmonic resonances of metallic nano-antennas between the far-field and near-field regimes. Here, we demonstrate that their interpretation of this effect is done under the same perspective as one recently reported in Langmuir 29, 6715 (2013); however, the former is incomplete and needs some remarks and clarifications which require additional relevant concepts and arguments of physical significance.