Molecule Non-Radiative Coupling to a Metallic Nanosphere: An Optical Theorem Treatment

The non-radiative coupling of a molecule to a metallic spherical particle is approximated by a sum involving particle quasistatic polarizabilities. We demonstrate that energy transfer from molecule to particle satisfies the optical theorem if size effects corrections are properly introduced into the quasistatic polarizabilities. We hope that this simplified model gives valuable information on the coupling mechanism between molecule and metallic nanos-tructures available for, e.g., surface enhanced spectroscopy signal analysis

In-plane remote photoluminescence excitation of carbon nanotube by propagating surface plasmon

In this work, we demonstrate propagating surface plasmon polariton (SPP) coupled photoluminescence (PL) excitation of single-walled carbon nanotube (SWNT). SPPs were launched at a few micrometers from individually marked SWNT, and plasmon-coupled PL was recorded to determine the efficiency of this remote in-plane addressing scheme. The efficiency depends upon the following factors: (i) longitudinal and transverse distances between the SPP launching site and the location of the SWNT and (ii) orientation of the SWNT with respect to the plasmon propagation wave vector (k SPP). Our experiment explores the possible integration of carbon nanotubes as a plasmon sensor in plasmonic and nanophotonic devices

Theory of molecular excitation and relaxation near a plasmonic device

International audienceThe new optical concepts currently developed in the research field of plasmonics can have significant practical applications for integrated optical device miniaturization as well as for molecular sensing applications. Particularly, these new devices can offer interesting opportunities for optical addressing of quantum systems. In this article, we develop a realistic model able to explore the various functionalities of a plasmon device connected to a single fluorescing molecule. We show that this theoretical method provides a useful framework to understand how quantum and plasmonic entities interact in a small area. Thus, the fluorescence signal evolution from excitation control to relaxation control depending on the incident light power is clearly observed

Laser-induced thermoelectric effects in electrically biased nanoscale constrictions

Electrically biased metal nanostructures are at the core of innovative multifunctional integrated devices that control the flow of electrons and photons at the nanoscale. They are based on plasmonic structures that create strongly confined fields, typically associated with large temperature gradients. These thermal effects may generate artifact responses detrimental to the desired operation. We show here how a biasing polarity and a local optical excitation asymmetry of a generic geometry – a nanoscale constriction – interplay thermally to modify the diffusive electron transport in out-of-equilibrium conditions. Our experimental results are accompanied with computational electromagnetism and multiphysics simulations

Optique sub-longueur d'onde et fluorescence moléculaire perturbée

Pdt. : A. Dereux (Univ. Dijon). Rapporteurs : O.J.F. Martin (ETH Zurich, Suisse) et S. Huant (Univ. Grenoble). Examinateurs : U. Fischer (Univ. Munster, ALL.) et A. Mlayah (Univ. Toulouse)Study of near-field optics interaction with a fluorescent molecule. We develop an original formalism able to describe the dynamic of molecule excited in near-field optics. It consists on introducing the field-susceptibility technic in the optical Bloch equations. Then, we apply this formalism to two configurations of scanning near-field optical microscopes using a single fluorescent molecule probe as a detector or a light source. In particular, we precise the role of the local density of states in the images formation. The last part opens up perspectives for the optical addressing of single molecule in coplanar geometry. We demonstrate the possiblity to realize sub-wavelength optical waveguides excited by an evanescent electric field.Interaction du champ proche optique avec une unique molecule fluorescente. Mise en place d'un formalisme couplant équations de Bloch optiques et susceptibilité du champ permettant de décrire la fluorescence déclenchée en champ proche. Application à l'interprétation d'images obtenus avec des microscopes en champ proche à sonde moléculaire (PSTM et SNOM). En particulier, mise en évidence du rôle de la densité locale d'états photoniques (LDOS) dans la formation des images. Introduction d'un nouveau concept de guide optique sub-longueur d'onde pour l'adressage moléculaire en géométrie coplanaire

Cavités plasmoniques et nanosources optiques

Les microcavités optiques présentent de hauts facteurs de qualité, c'est pourquoi ces systèmes sont d'un grand intérêt pour la conception de lasers à bas seuil, ou encore, pour l'étude du régime de couplage fort. En revanche, ces systèmes sont soumis à la limite de diffraction de la lumière, et donc les modes qu'ils supportent ont une extension spatiale ne pouvant être en deçà de l'échelle de la longueur d'onde. Dans ce manuscrit de thèse, nous nous intéressons aux systèmes plasmoniques parce qu'ils supportent des modes confinés à l'échelle nanométrique. En premier lieu, nous étudions une microcavité plasmonique planaire, constituée de deux miroirs plasmoniques qui piègent les ondes de surface au sein du système. Nous sondons spatialement les modes de la cavité en mesurant le temps de vie de fluorescence de molécules individuelles dispersées au sein du système. Puis, nous nous intéressons au confinement en 3 dimensions de modes supportés par des nanoparticules métalliques sphériques. Nous discutons de la définition du volume modal basée sur le calcul du confinement d'énergie autour de la particule. Ensuite, nous étudions l'exaltation de fluorescence d'ions de terres rares au sein d'une particule plasmonique de configuration coeur-coquille. Enfin, nous perturbons la photodynamique d'émission d'une source de photon unique en approchant à proximité l'extrémité d'une pointe plasmoniqueOptical microcavities exhibit high resonance quality, so that, they are of key interest for the design of low-threshold lasers or for achieving strong coupling regime. But, such systems support modes whose the volume remain diffraction limited.In this manuscript, we are interested in their plasmonic counterparts because they support confined modes at the sub-wavelength scale. First, we study an in-plane plasmonic cavity which is the transposition of 1D optical cavity to surface wave. We characterize the cavity by measuring the fluorescence lifetime of dye molecules deposited inside.Then, we are interested in 3-dimension mode confinement achieved by spherical metal nanoparticles. We discuss on the definition of the mode volume used in cavity quantum electrodynamic and based on the calculation of energy confinement around the particle. We also simulate the fluorescence enhancement of rare-earth ions embedded inside core-shell plasmonic particles. Finally, we disturb the photodynamic emission of a single-photon source by puttingthe extremity of a plasmonic tip nearby the emitterDIJON-BU Doc.électronique (212319901) / SudocSudocFranceF