Multimode plasmon excitation and in-situ analysis in top-down fabricated plasmonic nanocircuits

TL;DR

This paper demonstrates the synthesis and in-situ analysis of multimode plasmonic excitations in top-down fabricated nanocircuits, revealing mode-specific behaviors and group velocities through far-field emission analysis.

Contribution

It introduces a method for selective excitation and modal analysis of multimode plasmons in nanocircuits using polarization-dependent excitation and far-field emission detection.

Findings

Successful excitation of symmetric and antisymmetric modes.

Mode-specific group velocities measured.

In-situ analysis of multimode plasmon dynamics achieved.

Abstract

We experimentally demonstrate synthesis and in-situ analysis of multimode plasmonic excitations in two-wire transmission lines supporting a symmetric and an antisymmetric eigenmode. To this end we irradiate an incoupling antenna with a diffraction-limited excitation spot exploiting a polarization- and position-dependent excitation efficiency. Modal analysis is performed by recording the far-field emission of two mode-specific spatially separated emission spots at the far end of the transmission line. To illustrate the power of the approach we selectively determine the group velocities of symmetric and antisymmetric contributions of a multimode ultrafast plasmon pulse.