nanoantenna directivity and enhancement

7/30/2019 Nanoantenna directivity and enhancement

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Tuesday, October 4. 15:00-16:00

Nanoantenna directivity and enhancement:

how to measure them, what do they mean ?

Jrme Wenger

Institut Fresnel (CNRS) Domaine Universitaire de Saint Jrme, Marseille 13013, France

Email:[email protected]

http://jw-photonics-inside.over-blog.org/

Abstract

This tutorial will look into more details into the definitions and the practical use of enhancement factorsand directivity in the context of plasmonic nanoantennas to control the photoluminescence of a quantum emitter.

Plasmonic antennas are receiving a considerable interest to manipulate the light-matter interaction

at the nanoscale, and improve the detection of single quantum emitters. Two figures of merit arecommonly introduced to quantify the influence of the plasmonic antenna: the luminescence

enhancement factor and the emission directivity.

Being widely used does not imply that they are correctly used by everyone.

This contribution aims at discussing into more details these two figures of merit, and avoid any

misconception. We will look into the formal definitions which are quite straightforward and then

focus on common mistakes or factors influencing the measured values. A special attention will be

devoted to experimental aspects. Single nanoapertures surrounded by shallow grooves will serve as a

practical illustration of a plasmonic antenna to enhance the fluorescence of molecules [1,2].

References

[1] H. Aouani, O. Mahboub, E. Devaux, H. Rigneault, T.W. Ebbesen, J. Wenger, Plasmonic antennas fordirectional sorting of fluorescence emission, Nano Lett.11, DOI: 10.1021/nl200772d(2011).

[2] H. Aouani, O. Mahboub, N. Bonod, E. Devaux, E. Popov, H. Rigneault, T.W. Ebbesen, J. Wenger, Bright

unidirectional fluorescence emission of molecules in a nanoaperture with plasmonic corrugations,Nano Lett.11,637-644 (2011).
mailto:[email protected]://jw-photonics-inside.over-blog.org/http://jw-photonics-inside.over-blog.org/http://jw-photonics-inside.over-blog.org/mailto:[email protected]


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Tuesday, October 4. 16:00-17:00

Mie theory for modelling plasmonic particles

Brian Stout


[email protected]

Abstract

The analytical basis for "Mie" theory is reviewed while emphasizing the light it shines on fundamentalscattering laws and theorems. The extensions of Mie theory provided by multiple-scattering theory are also

reviewed and we illustrate some of their more notable physical predictions concerning hot spots and collectiveexcitations. We also review recent advances of this formalism concerning the properties of nano-antennas:

notably the modifications they confer on quantum emitter lifetimes and radiation diagrams.

"Mie" theory (as it is often called) provides analytical expressions for the scattering and

absorption of electromagnetic waves by homogeneous isotropic spherical particles. The quasi-exact

nature of this theory has proved invaluable in both the qualitative understanding and quantitative

simulations of light interacting with systems containing small particle inclusions.

Although localized plasmon excitations are often modelled as point electric dipoles, Mie theory

has proved indispensable in understanding finite size effects and the radiation properties of localized

plasmon resonances.

In this tutorial, we shall introduce the theoretical basis for deriving Mie theory while placing an

emphasis on its physical content. Notably, we show how these formulas illuminate some fundamentalscattering theorems and properties such as the unitary limit, optical theorem, and Ward identities.

The utility of Mie theory has been greatly extended in recent decades, by coupling it with quasi-

analytic multiple-scattering theories. We review the principles of these extensions which generalize

the quasi-exact results of "Mie" theory to plasmonic systems containing multiple particles, thus

yielding precise predictions of both near and far-field quantities.[1]

Even more recently, Mie theory has been improved to yield insights into nano-antenna design by

allowing rapid predictions for the modifications the antenna confers on the decay rates and radiation

diagrams of nearby quantum emitters.[2]

Some surprising predictions and novel designs are discussed

in this context.

References

[1] B.Stout, J.C.Auger, A.Devilez, Recursive T matrix algorithm for resonant multiple scattering: Applicationsto localized plasmon excitations ,J. Opt. Soc. Am. A, 25, pp:2549-2557, (2008).

[2] B.Stout, A.Devilez, B.Rolly, N.Bonod, Multipole methods for Nano-antennas design : applications to Yagi-

Uda configurationsJ. Opt. Soc. Am. B28 pp:1213:1223 (2011)


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Wednesday, October 5. 15:00-16:00

Nonlinear plasmonics

Sophie Brasselet

Institut Fresnel (CNRS) Domaine Universitaire de Saint Jrme, Marseille 13013, France* Email: [email protected]

Abstract

We will present basics and recent advances in nonlinear optics, applied to metallic nanostructures.

Linear optical responses from metallic nanostructures are essentially governed by plasmons,

which result in the confinement of optical fields within sub-wavelength size regions. This confinement

can result in significant enhancements of their nonlinear responses [1], which involve higher powers

of the incident optical fields. Nonlinear fields enhancements which can lead to interesting applications

such as efficient generation of optical harmonics from new types of nano-emitters for imaging [2,3],

ultra-sensitive detection of molecules at the surface of metals [4], active optical fields nano-

manipulation and routing in engineered nanostructures [5], as well as new nonlinear nano-probes to

characterize coherent properties of optical fields at the nano-scale [6]. While such applications already

emerge today, nonlinear optical properties of metallic nanostructures are still at the center of a large

amount of research, principally because understanding their underlying mechanisms requires refined

modelling and experimental techniques.

We will review in this lecture the basics of nonlinear optics and apply it to optical harmonics

generation in metallic nanoparticles (Fig. 1). In a second part, a few recent applications of nonlinear

optics in the fields of nano-plasmonics will be described, from single particle imaging to the coherent

control of ultra-short optical pulses at the nano-scale.

50nm Fig.1 Schematic representation of the generation of harmonics of the incident light by a non-centrosymmetric

metallic nanoparticle.

*Some of the works presented in this lecture have been obtained in collaboration with H. Shen, N. Nguyen, T.Toury, UTT Troyes, France, and P. Schn, V. Maillard, Institut Fresnel, Marseille, France.

References[1] M.I. Stockman, D.J. Bergman, C. Anceau, S. Brasselet, J. Zyss, Enhanced second harmonic generation by

nanorough metal surfaces, Phys. Rev. Lett., 92, 057402 (2004)

[2] M. Lippitz, M. A. van Dijk, and M.Orrit, Third-Harmonic Generation from Single Gold Nanoparticles,NanoLett. 5, 799-802 (2005)[3] J. Butet, J. Duboisset, G. Bachelier, I. Russier-Antoine, E. Benichou, C. Jonin, and P.F. Brevet , OpticalSecond Harmonic Generation of Single Metallic Nanoparticles Embedded in a Homogeneous Medium, NanoLett. 10, 1717 (2010).[4] P. Guyot-Sionnest, W. Chen, and Y. R. Shen, General considerations of optical second harmonic generationfrom surfaces and interfaces, Phys. Rev. B 33, 8254 (1986).

[5] T. Utikal, M.I. Stockman, A.P. Heberle, M. Lippitz, H. Giessen, All-Optical Control of the UltrafastDynamics of a Hybrid Plasmonic System, Phys. Rev. Lett. 104, 113903 (2010)[6] A. Bouhelier, M. Beversluis, A. Hartschuh, and L. Novotny, Near-Field Second-Harmonic GenerationInduced by Local Field Enhancement, Phys. Rev. Lett.90, 013903 (2003).


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Wednesday, October 5. 16:00-17:00

Manipulating surface plasmons with transformational optics

Sebastien Guenneau


The emerging field of transformational optics allows for a markedly enhanced control of the

electromagnetic wave trajectories within metamaterials popularized by fascinating paradigms ranging

from perfect lenses to invisibility cloaks, carpets, concentrators and rotators. In this tutorial, I will

review recent experimental results for heterogeneous meta-surfaces designed using the tool of

transformational plasmonics, in order to achieve a similar control for surface plasmon polaritons.

nanoantenna directivity and enhancement

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