Probing the Quantum Tunneling Limit of Plasmonic Enhancement by Third Harmonic Generation

Metal nanostructures provide extreme focusing of optical energy that is limited fundamentally by quantum tunneling. We directly probe the onset of the quantum tunneling regime observed by a sharp reduction in the local field intensity in subnanometer self-assembled monolayer gaps using third harmoni...

Full description

Saved in:
Bibliographic Details
Published in:Nano letters 2014-11, Vol.14 (11), p.6651-6654
Main Authors: Hajisalem, Ghazal, Nezami, Mohammedreza S, Gordon, Reuven
Format: Article
Language:English
Subjects:
Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Condensed matter: structure, mechanical and thermal properties
Cross-disciplinary physics: materials science
rheology
Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures
Exact sciences and technology
Focusing
Harmonic generations
Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties
Materials science
Methods of nanofabrication
Nanostructure
Nonlinear optics
Physics
Plasmonics
Quantum tunnelling
Self-assembled monolayers
Self-assembly
Spectra
Surface and interface electron states
Surfaces and interfaces
thin films and whiskers (structure and nonelectronic properties)
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Metal nanostructures provide extreme focusing of optical energy that is limited fundamentally by quantum tunneling. We directly probe the onset of the quantum tunneling regime observed by a sharp reduction in the local field intensity in subnanometer self-assembled monolayer gaps using third harmonic generation. Unlike past works that have inferred local limits from far-field spectra, this nonlinear measurement is sensitive to the near-field intensity as the third power. We calculate the local field intensity using a quantum corrected model and find good quantitative agreement with the measured third harmonic. The onset of the quantum regime occurs for double the gap size of past studies because of the reduced barrier height of the self-assembled monolayer, which will be critical for many applications of plasmonics, including nonlinear optics and surface enhanced Raman spectroscopy.
ISSN:1530-6984
1530-6992
DOI:10.1021/nl503324g