Wavevector analysis of plasmon-assisted distributed nonlinear photoluminescence along Au nanowire antennas

TL;DR

This study provides a detailed wavevector analysis of plasmon-assisted nonlinear photoluminescence along gold nanowires, revealing polarization-dependent emission patterns and validating findings with finite element simulations.

Contribution

It introduces a quantitative wavevector analysis method for nonlinear photoluminescence in nanowires and demonstrates polarization effects with simulation validation.

Findings

Nanowires emit polarized nonlinear photoluminescence with distinct wavevector characteristics.

Directional scattering is accurately simulated using finite element methods.

Polarization influences the emission pattern and wavevector distribution.

Abstract

We report a quantitative analysis of the wavevector diagram emitted by nonlinear photoluminescence generated by a tightly focused pulsed laser beam and distributed along Au nanowire via the mediation of surface plasmon polaritions. The nonlinear photoluminescence is locally excited at key locations along the nanowire in order to understand the different contributions constituting the emission pattern measured in a conjugate Fourier plane of the microscope. Polarization-resolved measurements reveal that the nanowire preferentially emits nonlinear photoluminescence polarized transverse to the long axis at close to the detection limit wavevectors with a small azimuthal spread in comparison to the signal polarized along the long axis. We utilize finite element method to simulate the observed directional scattering by using localized incoherent sources placed on the nanowire. Simulation results faithfully mimic the directional emission of the nonlinear signal emitted by the different portions of the nanowire.