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Tunable dark plasmons in a metallic nanocube dimer : Toward ultimate sensitivity nanoplasmonic sensors

Zhang, Shunping and Xu, Hongxing LU (2016) In Nanoscale 8(28). p.13722-13729
Abstract

Metallic nanoparticles can function as label-free nanosensors monitoring the local dielectric environment in their close vicinity, thanks to the localized surface plasmon resonances. The sensing figure of merit is limited by the total loss rate of the plasmon. Here, we theoretically study a silver nanocube dimer and discover for the first time a dark plasmon with its total loss rate at the lower theoretical limit. It originates from the attractive coupling of the dipolar and quadrupolar mode in the individual nanocubes. It shows an unprecedented sensitivity to the interparticle gap distance, i.e., one ångström change in the gap distance results in a shift twice as large as the peak width. The sensing figure of merit using this dark... (More)

Metallic nanoparticles can function as label-free nanosensors monitoring the local dielectric environment in their close vicinity, thanks to the localized surface plasmon resonances. The sensing figure of merit is limited by the total loss rate of the plasmon. Here, we theoretically study a silver nanocube dimer and discover for the first time a dark plasmon with its total loss rate at the lower theoretical limit. It originates from the attractive coupling of the dipolar and quadrupolar mode in the individual nanocubes. It shows an unprecedented sensitivity to the interparticle gap distance, i.e., one ångström change in the gap distance results in a shift twice as large as the peak width. The sensing figure of merit using this dark plasmon is 56-61, reaching the ultimate value limited only by the material permittivity. The field of the mode is confined mainly within the gap region which is in the extreme deep subwavelength (3.5 × 10-6λ0 3) region. Besides sensing applications, the dark plasmon also shows foreseeable potential in enhanced spectroscopy, nanolasers and other nanophotonic devices.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Nanoscale
volume
8
issue
28
pages
8 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:84978708960
  • wos:000380021100026
ISSN
2040-3364
DOI
10.1039/c6nr03806a
language
English
LU publication?
yes
id
68ca919f-e09c-41e6-9c50-04d0a7c3e985
date added to LUP
2016-12-19 14:07:37
date last changed
2017-10-29 04:55:42
@article{68ca919f-e09c-41e6-9c50-04d0a7c3e985,
  abstract     = {<p>Metallic nanoparticles can function as label-free nanosensors monitoring the local dielectric environment in their close vicinity, thanks to the localized surface plasmon resonances. The sensing figure of merit is limited by the total loss rate of the plasmon. Here, we theoretically study a silver nanocube dimer and discover for the first time a dark plasmon with its total loss rate at the lower theoretical limit. It originates from the attractive coupling of the dipolar and quadrupolar mode in the individual nanocubes. It shows an unprecedented sensitivity to the interparticle gap distance, i.e., one ångström change in the gap distance results in a shift twice as large as the peak width. The sensing figure of merit using this dark plasmon is 56-61, reaching the ultimate value limited only by the material permittivity. The field of the mode is confined mainly within the gap region which is in the extreme deep subwavelength (3.5 × 10<sup>-6</sup>λ<sub>0</sub> <sup>3</sup>) region. Besides sensing applications, the dark plasmon also shows foreseeable potential in enhanced spectroscopy, nanolasers and other nanophotonic devices.</p>},
  author       = {Zhang, Shunping and Xu, Hongxing},
  issn         = {2040-3364},
  language     = {eng},
  month        = {07},
  number       = {28},
  pages        = {13722--13729},
  publisher    = {Royal Society of Chemistry},
  series       = {Nanoscale},
  title        = {Tunable dark plasmons in a metallic nanocube dimer : Toward ultimate sensitivity nanoplasmonic sensors},
  url          = {http://dx.doi.org/10.1039/c6nr03806a},
  volume       = {8},
  year         = {2016},
}