Jump to main content
Jump to site search

Issue 24, 2014
Previous Article Next Article

Refractive index sensing with Fano resonant plasmonic nanostructures: a symmetry based nonlinear approach

Author affiliations

Abstract

Sensing using surface plasmon resonances is one of the most promising practical applications of plasmonic nanostructures and Fano resonances allow achieving a lower detection limit thanks to their narrow spectral features. However, a narrow spectral width of the subradiant mode in a plasmonic system, as observed in the weak coupling regime, is in general associated with a low modulation of the complete spectral response. In this article, we show that this limitation can be overcome by a nonlinear approach based on second harmonic generation and its dependence on symmetry at the nanoscale. The Fano resonant systems considered in this work are gold nanodolmens. Their linear and nonlinear responses are evaluated using a surface integral equation method. The numerical results demonstrate that a variation of the refractive index of the surrounding medium modifies the coupling between the dark and bright modes, resulting in a modification of the electromagnetic wave scattered at the second harmonic wavelength, especially the symmetry of the nonlinear emission. Reciprocally, we show that evaluating the asymmetry of the nonlinear emission provides a direct measurement of the gold nanodolmens dielectric environment. Interestingly, the influence of the refractive index of the surrounding medium on the nonlinear asymmetry parameter is approximately 10 times stronger than on the spectral position of the surface plasmon resonance: hence, smaller refractive index changes can be detected with this new approach. Practical details for an experimental realization of this sensing scheme are discussed and the resolution is estimated to be as low as Δn = 1.5 × 10−3, respectively 1.5 × 10−5, for an acquisition time of 60 s for an isolated gold nanodolmen, respectively an array of 10 × 10 nanodolmens.

Graphical abstract: Refractive index sensing with Fano resonant plasmonic nanostructures: a symmetry based nonlinear approach

Back to tab navigation

Supplementary files

Article information


Submitted
25 Sep 2014
Accepted
28 Oct 2014
First published
03 Nov 2014

Nanoscale, 2014,6, 15262-15270
Article type
Paper

Refractive index sensing with Fano resonant plasmonic nanostructures: a symmetry based nonlinear approach

J. Butet and O. J. F. Martin, Nanoscale, 2014, 6, 15262 DOI: 10.1039/C4NR05623J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements