Analysis of damping-induced phase flips of plasmonic nanowire modes

TL;DR

This paper investigates how damping affects phase flips in plasmonic modes of silver nanowires, revealing a new method to detect environmental absorption changes via phase behavior.

Contribution

It introduces a generalized Fabry-Perot model to explain phase flips caused by damping in nanowire plasmon modes, enabling environmental sensing.

Findings

Spectral maxima and minima are either in phase or out of phase depending on nanowire length.

The phase flip behavior is explained by a generalized Fabry-Perot model.

The turnover point is sensitive to surface plasmon round trip losses.

Abstract

We launch surface plasmons from one end of a silver nanowire by asymmetric illumination with white light and use plasmon-to-light scattering at the nanowire ends to probe spectroscopically the plasmonic Fabry-Perot wire modes. The spectral positions of the maxima and minima in the scattered intensity from both nanowire ends are found to be either in phase or out-of phase, depending on the nanowire length and the spectral range. This behavior can be explained by a generalized Fabry-Perot model. The turnover-point between the two regimes is sensitive to the surface plasmon round trip losses and thus opens a new possibility for detecting changes of the optical absorption in the nanowire environment.