Publications of the Research Group Computational Photonics

Prof. Dr. Antonio Calà Lesina

Origin of third harmonic generation in plasmonic nanoantennas

authored by
Antonino Calà Lesina, Pierre Berini, Lora Ramunno
Abstract

Plasmonic nanoantennas have been recently proposed to boost nonlinear optical processes. In a metal dipole nanoantenna with a dielectric nanoparticle placed in the gap, the linear field enhancement can be exploited to enhance third harmonic emission. Since both metals and dielectrics exhibit nonlinearity, the nonlinear far-field contains contributions from each, and the diffculty of measuring these contributions separately has led to seemingly contradictory interpretations about the origin of the nonlinear emission. We determine that the origin of the third harmonic from metal-dielectric dipole nanoantennas depends on nanoantenna design, and in particular, the width. We find that the emission from gold dominates in thin threadlike nanoantennas, whereas the emission from the gap material dominates in wider nanoantennas. We also find that the nonlinear emission from gold in dipole nanoantennas is lower than monopoles of comparable dimensions, but that placing a highly nonlinear material in their gaps makes the nonlinear emission from the gap material dominate over gold.

External Organisation(s)
University of Ottawa
Type
Article
Journal
Optical materials express
Volume
7
Pages
1575-1580
No. of pages
6
ISSN
2159-3930
Publication date
11.04.2017
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials
Electronic version(s)
https://doi.org/10.1364/OME.7.001575 (Access: Unknown)