Absorption and optimal plasmonic resonances for small ellipsoidal particles in lossy media
Dalarsson, Mariana ; Nordebo, Sven LU ; Sjöberg, Daniel LU
and Bayford, Richard
(2017)
In Journal of Physics D: Applied Physics
50(34).
- Abstract
A new simplifed formula is derived for the absorption cross section of small dielectric ellipsoidal particles embedded in lossy media. The new expression leads directly to a closed form solution for the optimal conjugate match with respect to the surrounding medium, i.e. the optimal permittivity of the ellipsoidal particle that maximizes the absorption at any given frequency. This defnes the optimal plasmonic resonance for the ellipsoid. The optimal conjugate match represents a metamaterial in the sense that the corresponding optimal permittivity function may have negative real part (inductive properties), and can not in general be implemented as a passive material over a given bandwidth. A necessary and suffcient condition is derived... (More)
A new simplifed formula is derived for the absorption cross section of small dielectric ellipsoidal particles embedded in lossy media. The new expression leads directly to a closed form solution for the optimal conjugate match with respect to the surrounding medium, i.e. the optimal permittivity of the ellipsoidal particle that maximizes the absorption at any given frequency. This defnes the optimal plasmonic resonance for the ellipsoid. The optimal conjugate match represents a metamaterial in the sense that the corresponding optimal permittivity function may have negative real part (inductive properties), and can not in general be implemented as a passive material over a given bandwidth. A necessary and suffcient condition is derived for the feasibility of tuning the Drude model to the optimal conjugate match at a single frequency, and it is found that all the prolate spheroids and some of the (not too flat) oblate spheroids can be tuned into optimal plasmonic resonance at any desired center frequency. Numerical examples are given to illustrate the analysis. Except for the general understanding of plasmonic resonances in lossy media, it is also anticipated that the new results can be useful for feasibility studies with e.g. the radiotherapeutic hyperthermia based methods to treat cancer based on electrophoretic heating in gold nanoparticle suspensions using microwave radiation.
(Less)
- author
- Dalarsson, Mariana
; Nordebo, Sven
LU
; Sjöberg, Daniel
LU
and Bayford, Richard
- organization
- publishing date
- 2017-07-31
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- absorption cross section, Particle absorption, plasmonic resonances
- in
- Journal of Physics D: Applied Physics
- volume
- 50
- issue
- 34
- article number
- 345401
- publisher
- IOP Publishing
- external identifiers
-
- scopus:85027258563
- wos:000406527200001
- ISSN
- 0022-3727
- DOI
- 10.1088/1361-6463/aa7c8a
- language
- English
- LU publication?
- yes
- id
- 9cc9b688-48cb-4841-9c99-b4da63921aae
- date added to LUP
- 2017-08-31 11:22:12
- date last changed
- 2024-10-14 11:59:22
@article{9cc9b688-48cb-4841-9c99-b4da63921aae,
abstract = {{<p>A new simplifed formula is derived for the absorption cross section of small dielectric ellipsoidal particles embedded in lossy media. The new expression leads directly to a closed form solution for the optimal conjugate match with respect to the surrounding medium, i.e. the optimal permittivity of the ellipsoidal particle that maximizes the absorption at any given frequency. This defnes the optimal plasmonic resonance for the ellipsoid. The optimal conjugate match represents a metamaterial in the sense that the corresponding optimal permittivity function may have negative real part (inductive properties), and can not in general be implemented as a passive material over a given bandwidth. A necessary and suffcient condition is derived for the feasibility of tuning the Drude model to the optimal conjugate match at a single frequency, and it is found that all the prolate spheroids and some of the (not too flat) oblate spheroids can be tuned into optimal plasmonic resonance at any desired center frequency. Numerical examples are given to illustrate the analysis. Except for the general understanding of plasmonic resonances in lossy media, it is also anticipated that the new results can be useful for feasibility studies with e.g. the radiotherapeutic hyperthermia based methods to treat cancer based on electrophoretic heating in gold nanoparticle suspensions using microwave radiation.</p>}},
author = {{Dalarsson, Mariana and Nordebo, Sven and Sjöberg, Daniel and Bayford, Richard}},
issn = {{0022-3727}},
keywords = {{absorption cross section; Particle absorption; plasmonic resonances}},
language = {{eng}},
month = {{07}},
number = {{34}},
publisher = {{IOP Publishing}},
series = {{Journal of Physics D: Applied Physics}},
title = {{Absorption and optimal plasmonic resonances for small ellipsoidal particles in lossy media}},
url = {{http://dx.doi.org/10.1088/1361-6463/aa7c8a}},
doi = {{10.1088/1361-6463/aa7c8a}},
volume = {{50}},
year = {{2017}},
}