Nonlinear Fano Profiles in the Optical Second-Harmonic Generation from Silver Nanoparticles

TL;DR

This paper investigates how interference between different plasmon resonances in silver nanoparticles affects second harmonic generation, revealing controllable nonlinear Fano profiles and transparency effects.

Contribution

It demonstrates experimentally and numerically that nonlinear Fano profiles in SHG can be controlled via polarization, advancing understanding of nonlinear plasmonic phenomena.

Findings

Fano profiles arise from interference of dipolar and octupolar resonances.

External polarization controls the Fano profiles.

Nonlinear plasmon-induced transparency observed in SHG.

Abstract

The resonance effects on the optical second harmonic generation from 140 nm silver nanoparticles is studied experimentally by hyper-Rayleigh scattering and numerically by finite element method calculations. We find that the interferences between the broad dipolar and narrow octupolar surface plasmon resonances leads to nonlinear Fano profiles that can be externally controlled by the incident polarization angle. These profiles are responsible for the nonlinear plasmon-induced transparency in the second harmonic generation.