Des nanotorches pour étudier les matériaux nanostructurés
Izeddin, I., and V. Krachmalnicoff
Photoniques, no. 114, 40-44 (2022)
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Single-emitter super-resolved imaging of radiative decay rate enhancement in dielectric gap nanoantennas
Córdova-Castro, R. M., B. Van Dam, A. Lauri, S. A. Maier, R. Sapienza, Y. De Wilde, I. Izeddin, and V. Krachmalnicoff
Light: Science and Applications 13, no. 1 (2024)
Résumé: High refractive index dielectric nanoantennas strongly modify the decay rate via the Purcell effect through the design of radiative channels. Due to their dielectric nature, the field is mainly confined inside the nanostructure and in the gap, which is hard to probe with scanning probe techniques. Here we use single-molecule fluorescence lifetime imaging microscopy (smFLIM) to map the decay rate enhancement in dielectric GaP nanoantenna dimers with a median localization precision of 14 nm. We measure, in the gap of the nanoantenna, decay rates that are almost 30 times larger than on a glass substrate. By comparing experimental results with numerical simulations we show that this large enhancement is essentially radiative, contrary to the case of plasmonic nanoantennas, and therefore has great potential for applications such as quantum optics and biosensing.
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Transition from Phononic to Geometrical Mie Modes Measured in Single Subwavelength Polar Dielectric Spheres
Abou-Hamdan, L., L. Coudrat, S. Bidault, V. Krachmalnicoff, R. Haïdar, P. Bouchon, and Y. De Wilde
ACS Photonics 9, no. 7, 2295-2303 (2022)
Résumé: Spherical dielectric resonators are highly attractive for light manipulation, thanks to their intrinsic electric and magnetic resonances. Here, we present measurements of the mid-infrared far-field thermal radiation of single subwavelength dielectric spheres deposited on a gold substrate, of radii ranging from 1 to 2.5 μm, which agree quantitatively with simulated absorption cross sections. For SiO2microspheres, we evidence the excitation of both surface phonon-polariton (SPhP) modes and geometrical electric and magnetic Mie modes. The transition from a phonon-mode-dominated to a Mie-mode-dominated emission spectrum is observed, with a threshold radius of ∼1.5 μm. We also show that the presence of the metallic substrate augments the computed spheres absorption cross-section due to increased local field enhancement, arising from the near-field interaction of the spheres oscillating charges with their image in the metallic mirror. In contrast, measurements of single subwavelength SPhP-inactive PTFE spheres reveal that the mid-infrared response of such lossy spheres is dominated by their bulk absorption. Our results demonstrate how engineering the geometrical and dielectric properties of subwavelength scatterers can enable the control of thermal emission near room temperature, with exciting perspectives for applications such as radiative cooling.
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Extended Hybridization and Energy Transfer in Periodic Multi-Material Organic Structures in Strong Coupling with Surface Plasmon
Bard, A., S. Minot, C. Symonds, J. M. Benoit, A. Gassenq, F. Bessueille, B. Andrioletti, C. Perez, K. Chevrier, Y. De Wilde, V. Krachmalnicoff, and J. Bellessa
Advanced Optical Materials (2022)
Résumé: The strong light−matter coupling, occurring when the light−matter interaction prevails on the damping, has found applications beyond the domain of optics in chemistry or transport. These advances make the development of various structures in strong coupling crucial. In this paper, a new way to hybridize two materials and transfer energy through a surface plasmon over micrometric distances is proposed. For this purpose, two patterned interlocked dye arrays, one donor and one acceptor, are deposited on a silver surface by successive micro-contact printing, leading to a pattern of 5 microns period. The dispersion relation of the structure is measured with reflectometry experiments, showing the hybridization with the plasmon, and the formation of states that mix both excitons and the plasmon with similar weights. The mixing in these polaritonic metasurfaces enables an energy transfer mechanism in the strong coupling, which is observed with luminescence experiments. As the donor and acceptor are spatially separated by a distance larger than the diffraction limit the excitation transfer is directly measured and evaluated by comparison with dye arrays without silver.
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Method to measure the refractive index for photoluminescence modelling
Bailly, E., K. Chevrier, C. P. De La Vega, J. P. Hugonin, Y. De Wilde, V. Krachmalnicoff, B. Vest, and J. J. Greffet
Optical Materials Express 12, no. 7, 2772-2781 (2022)
Résumé: Light emission by fluorophores can be computed from the knowledge of the absorption spectrum. However, at long wavelengths, the calculated emission may diverge if the decay of the imaginary part of the permittivity is not modelled with precision. We report a technique to obtain the permittivity of fluorophores such as dye molecules from fluorescence measurements. We find that the Brendel-Bormann model enables to fit the emission spectra accurately.
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Super-resolution imaging: When biophysics meets nanophotonics
Koenderink, A. F., R. Tsukanov, J. Enderlein, I. Izeddin, and V. Krachmalnicoff
Nanophotonics 11, no. 2, 169-202 (2022)
Résumé: Probing light-matter interaction at the nanometer scale is one of the most fascinating topics of modern optics. Its importance is underlined by the large span of fields in which such accurate knowledge of light-matter interaction is needed, namely nanophotonics, quantum electrodynamics, atomic physics, biosensing, quantum computing and many more. Increasing innovations in the field of microscopy in the last decade have pushed the ability of observing such phenomena across multiple length scales, from micrometers to nanometers. In bioimaging, the advent of super-resolution single-molecule localization microscopy (SMLM) has opened a completely new perspective for the study and understanding of molecular mechanisms, with unprecedented resolution, which take place inside the cell. Since then, the field of SMLM has been continuously improving, shifting from an initial drive for pushing technological limitations to the acquisition of new knowledge. Interestingly, such developments have become also of great interest for the study of light-matter interaction in nanostructured materials, either dielectric, metallic, or hybrid metallic-dielectric. The purpose of this review is to summarize the recent advances in the field of nanophotonics that have leveraged SMLM, and conversely to show how some concepts commonly used in nanophotonics can benefit the development of new microscopy techniques for biophysics. To this aim, we will first introduce the basic concepts of SMLM and the observables that can be measured. Then, we will link them with their corresponding physical quantities of interest in biophysics and nanophotonics and we will describe state-of-the-art experiments that apply SMLM to nanophotonics. The problem of localization artifacts due to the interaction of the fluorescent emitter with a resonant medium and possible solutions will be also discussed. Then, we will show how the interaction of fluorescent emitters with plasmonic structures can be successfully employed in biology for cell profiling and membrane organization studies. We present an outlook on emerging research directions enabled by the synergy of localization microscopy and nanophotonics.
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Single-molecule imaging of LDOS modification by an array of plasmonic nanochimneys
Margoth Cordova-Castro, R., D. Jonker, B. Van Dam, G. Blanquer, Y. De Wilde, I. Izeddin, A. Susarrey-Arce, and V. Krachmalnicoff
2021 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2021 (2021)
Résumé: The direct measurement of a single emitter decay rate and the simultaneous knowledge of their position is a powerful tool for the study of light-matter interaction at the nanometer scale. In particular, the decay rate is directly related to the local density of states (LDOS) which measures the number of modes of the electromagnetic environment available for the decay of an emitter.
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Near-field and far-field studies of single and double sub-λ sized infrared plasmonic nano-antennas
Abou Hamdan, L., V. Krachmalnicoff, R. Haidar, P. Bouchon, and Y. De Wilde
2021 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2021 (2021)
Résumé: The electromagnetic modes of a sub-wavelength sized antenna can be excited by thermal fluctuations. This thermal radiation is extremely weak, requiring in general the fabrication of a huge number of identical antennas to be detectable. Here, we will first demonstrate experimentally emission spectrum measurement and superresolved mapping of a single nanoantenna, sub-λ in the infrared spectral domain, based on the detection of its thermal radiation despite an overwhelming background thermal radiation [1]. To achieve a background free detection of the thermal radiation from single or a few sub-λ sized resonators, we have developed an infrared spatial modulation spectroscopy (IR-SMS) technique using a lateral modulation of the sample heated at ~150 °C combined with lock-in detection of the infrared signal detected through a Fourier transform infrared spectrometer. We have applied it in combination with thermal radiation scanning tunnelling microscopy [2] to study the thermal radiation from single plasmonic metal-insulator-metal (MIM) antennas both in the near field and in the far field. Our studies performed on single MIMs have revealed the surprising result that when silica is used as insulating material, its strong dispersion in the mid-infrared domain is such that the fundamental spatial mode of the antenna can be thermally excited at various wavelengths. This causes multiple resonances in the thermal radiation spectrum to which correspond the same spatial distribution of near-field thermal radiation [1].
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Waveguide efficient directional coupling and decoupling via an integrated plasmonic nanoantenna
Blanquer, G., V. Loo, N. Rahbany, C. Couteau, S. Blaize, R. Salas-Montiel, Y. De Wilde, and V. Krachmalnicoff
Optics Express 29, no. 18, 29034-29043 (2021)
Résumé: The development of integrated photonic devices has led to important advancements in the field of light-matter interaction at the nanoscale. One of the main focal points is the coupling between single photon emitters and optical waveguides aiming to achieve efficient optical confinement and propagation. In this work, we focus on the characterization of a hybrid dielectric/plasmonic waveguide consisting of a gold triangular nanoantenna placed on top of a TiO2 waveguide. The strong directionality of the device is experimentally demonstrated by comparing the intensity scattered by the nanotriangle to the one scattered by a SNOM tip for different illumination geometries. The ability of the plasmonic antenna to generate powerful coupling between a single emitter and the waveguide will also be highlighted through numerical simulations.
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Hybrid modes in a single thermally excited asymmetric dimer antenna
Abou-Hamdan, L., C. Li, R. Haidar, V. Krachmalnicoff, P. Bouchon, and Y. De Wilde
Optics Letters 46, no. 5, 981-984 (2021)
Résumé: The study of hybrid modes in a single dimer of neighboring antennas is an essential step to optimize the far-field electromagnetic (EM) response of large-scale metasurfaces or any complex antenna structure made up of subwavelength building blocks. Here we present far-field infrared spatial modulation spectroscopy (IR-SMS) measurements of a single thermally excited asymmetric dimer of square metal-insulator-metal (MIM) antennas separated by a nanometric gap. Through thermal fluctuations, all the EM modes of the antennas are excited, and hybrid bonding and anti-bonding modes can be observed simultaneously. We study the latter within a plasmon hybridization model, and analyze their effect on the far-field response.
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Quantitative Measurement of the Thermal Contact Resistance between a Glass Microsphere and a Plate
Doumouro, J., E. Perros, A. Dodu, N. Rahbany, D. Leprat, V. Krachmalnicoff, R. Carminati, W. Poirier, and Y. De Wilde
Physical Review Applied 15, no. 1 (2021)
Résumé: © 2021 American Physical Society. Accurate measurements of the thermal resistance between micro-objects made of insulating materials are complex because of their small size, low conductivity, and the presence of various ill-defined gaps. We address this issue using a modified scanning thermal microscope operating in vacuum and in air. The sphere-plate geometry is considered. Under controlled heating power, we measure the temperature on top of a glass microsphere glued to the probe as it approaches a glass plate at room temperature with nanometer accuracy. In vacuum, a jump is observed at contact. From this jump in temperature and the modeling of the thermal resistance of a sphere, the sphere-plate contact resistance RK=(1.4±0.18)×107KW-1 and effective radius r=36±4 nm are obtained. In air, the temperature on top of the sphere shows a decrease starting from a sphere-plate distance of 200μm. A jump is also observed at contact, with a reduced amplitude. The sphere-plate coupling out of contact can be described by the resistance shape factor of a sphere in front of a plate in air, placed in a circuit involving a series and a parallel resistance that are determined by fitting the approach curve. The contact resistance in air RK - =(1.2±0.46)×107KW-1 is then estimated from the temperature jump. The method is quantitative without requiring any tedious multiple-scale numerical simulation, and is versatile to describe the coupling between micro-objects from large distances to contact in various environments.
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Relocating Single Molecules in Super-Resolved Fluorescence Lifetime Images near a Plasmonic Nanostructure
Blanquer, G., B. Van Dam, A. Gulinatti, G. Acconcia, Y. De Wilde, I. Izeddin, and V. Krachmalnicoff
ACS Photonics 7, no. 2, 393-400 (2020)
Résumé: Copyright © 2020 American Chemical Society. Single-molecule localization microscopy is a powerful technique with vast potential to study light-matter interactions at the nanoscale. Nanostructured environments can modify the fluorescence emission of single molecules, and the induced decay-rate modification can be retrieved to map the local density of optical states (LDOS). However, the modification of the emitter's point spread function (PSF) can lead to its mislocalization, setting a major limitation to the reliability of this approach. In this paper, we address this by simultaneously mapping the position and decay rate of single molecules and by sorting events by their decay rate and PSF size. With the help of numerical simulations, we are able to infer the dipole orientation and to retrieve the real position of mislocalized emitters. We have applied our approach of single-molecule fluorescence lifetime imaging microscopy (smFLIM) to study the LDOS modification of a silver nanowire over a field of view of ∼ 10 μm2 with a single-molecule localization precision of ∼ 15 nm. This is possible thanks to the combined use of an EMCCD camera and an array of single-photon avalanche diodes, enabling multiplexed and super-resolved fluorescence lifetime imaging.
Mots-clés: decay rate; local density of optical states (LDOS); mislocalization; point spread function (PSF); single-molecule fluorescence lifetime imaging microscopy (smFLIM); single-molecule localization microscopy (SMLM)
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Thermal emission from a single glass fiber
Kallel, H., J. Doumouro, V. Krachmalnicoff, Y. De Wilde, and K. Joulain
Journal of Quantitative Spectroscopy and Radiative Transfer 236 (2019)
Résumé: © 2019 In this article, we study the thermal light emission from individual fibers of an industrial glass material, which are elementary building blocks of glass wool boards used for thermal insulation. Thermal emission spectra of single fibers of various diameters partially suspended on air are measured in the far field by means of infrared spatial modulation spectroscopy. These experimental spectra are compared with the theoretical absorption efficiency spectra of cylindrical shaped fibers calculated analytically in the framework of Mie theory taking as an input the measured permittivity of the industrial glass material. An excellent qualitative agreement is found between the measured thermal radiation spectra and the theoretical absorption efficiency spectra.
Mots-clés: Far-field thermal radiation; Glass fiber; Mie theory; Single object; Spatial modulation spectroscopy
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Cramér-Rao analysis of lifetime estimations in time-resolved fluorescence microscopy
Bouchet, D., V. Krachmalnicoff, and I. Izeddin
Optics Express 27, no. 15, 21239-21252 (2019)
Résumé: © 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement Measuring the lifetime of fluorescent emitters by time-correlated single photon counting (TCSPC) is a routine procedure in many research areas spanning from nanophotonics to biology. The precision of such measurement depends on the number of detected photons but also on the various sources of noise arising from the measurement process. Using Fisher information theory, we calculate the lower bound on the precision of lifetime estimations for mono-exponential and bi-exponential distributions. We analyse the dependence of the lifetime estimation precision on experimentally relevant parameters, including the contribution of a non-uniform background noise and the instrument response function (IRF) of the setup. We also provide an open-source code to determine the lower bound on the estimation precision for any experimental conditions. Two practical examples illustrate how this tool can be used to reach optimal precision in time-resolved fluorescence microscopy.
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Near-Field and Far-Field Thermal Emission of Individual Subwavelength-Sized Resonators
Li, C., H. Kallel, J. Doumouro, V. Krachmalnicoff, P. Bouchon, J. Jaeck, N. Bardou, K. Joulain, R. Haidar, and Y. De Wilde
2019 Conference on Lasers and Electro-Optics, CLEO 2019 - Proceedings (2019)
Résumé: © 2019 The Author(s) 2019 OSA. We propose a modulation method to record background-free far field FTIR spectra of single sub -lambda sized objects which we combine with near-field TRSTM measurements to characterize the thermal emission of plasmonic antennas and silica rods. The fundamental mode of MIM nanoantennas is excited at multiple wavelengths.
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Probing near-field light-matter interactions with single-molecule lifetime imaging
Bouchet, D., J. Scholler, G. Blanquer, Y. De Wilde, I. Izeddin, and V. Krachmalnicoff
Optica 6, no. 2, 135-138 (2019)
Résumé: © 2019 Optical Society of America. Nanophotonics offers a promising range of applications spanning from the development of efficient solar cells to quantum communications and biosensing. However, the ability to efficiently couple fluorescent emitters with nanostructured materials requires one to probe light-matter interactions at a subwavelength resolution, which remains experimentally challenging. Here, we introduce an approach to performsuperresolved fluorescence lifetime measurements on samples that are densely labeled with photo-activatable fluorescent molecules. The simultaneous measurement of the position and the decay rate of the molecules provides direct access to the local density of states (LDOS) at the nanoscale.We experimentally demonstrate the performance of the technique by studying the LDOS variations induced in the near field of a silver nanowire, and we show via a Cramér-Rao analysis that the proposed experimental setup enables a single-molecule localization precision of 6 nm.
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Imaging light scattered by a subwavelength nanofiber, from near field to far field
Loo, V., G. Blanquer, M. Joos, Q. Glorieux, Y. De Wilde, and V. Krachmalnicoff
Optics Express 27, no. 2, 350-357 (2019)
Résumé: © 2019 Optical Society of America. We present a direct experimental investigation of the optical field distribution around a suspended tapered optical nanofiber by means of a fluorescent scanning probe. Using a 100 nm diameter fluorescent bead as a probe of the field intensity, we study interferences made by a nanofiber (400 nm diameter) scattering a plane wave (568 nm wavelength). Our scanning fluorescence near-field microscope maps the optical field over 36 µm2, with λ/5 resolution, from contact with the surface of the nanofiber to a few micrometers away. Comparison between experiments and Mie scattering theory allows us to precisely determine the emitter-nanofiber distance and experimental drifts.
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Near-Field and Far-Field Thermal Emission of an Individual Patch Nanoantenna
Li, C., V. Krachmalnicoff, P. Bouchon, J. Jaeck, N. Bardou, R. Haïdar, and Y. De Wilde
Physical Review Letters 121, no. 24 (2018)
Résumé: © 2018 American Physical Society. The far-field spectral and near-field spatial responses of an individual metal-insulator-metal nanoantenna are reported, using thermal fluctuations as an internal source of the electromagnetic field. The far-field spectra, obtained by combining Fourier transform infrared spectroscopy with spatial modulation based on a light falloff effect in a confocal geometry, have revealed two distinct emission peaks attributed to the excitation of the fundamental mode of the nanoantenna at two distinct wavelengths. Superresolved near-field images of the thermally excited mode have been obtained by thermal radiation scanning tunneling microscopy. Experimental results are supported by numerical simulations showing that it is possible to excite the same mode at different wavelengths near a resonance of the insulating dielectric material forming the antenna.
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Polarization Control of Linear Dipole Radiation Using an Optical Nanofiber
Joos, M., C. Ding, V. Loo, G. Blanquer, E. Giacobino, A. Bramati, V. Krachmalnicoff, and Q. Glorieux
Physical Review Applied 9, no. 6 (2018)
Résumé: © 2018 American Physical Society. We experimentally demonstrate that a linear dipole is not restricted to emit linearly polarized light, provided that it is embedded in the appropriate nanophotonic environment. We observe emission of various elliptical polarizations by a linear dipole, including circularly polarized light, without the need for birefringent components. We further show that the emitted state of polarization can theoretically span the entire Poincaré sphere. The experimental demonstration is based on elongated gold nanoparticles (nanorods) deposited on an optical nanofiber and excited by a free-space laser beam. The light directly collected in the guided mode of the nanofiber is analyzed in regard to the azimuthal position and orientation of the nanorods, observed by means of scanning electron microscopy. We demonstrate a mapping between purely geometrical degrees of freedom of a light source and all polarization states that could open the way to alternative methods for polarization control of light sources at the nanoscale.
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One-Shot Measurement of the Three-Dimensional Electromagnetic Field Scattered by a Subwavelength Aperture Tip Coupled to the Environment
Rahbany, N., I. Izeddin, V. Krachmalnicoff, R. Carminati, G. Tessier, and Y. De Wilde
ACS Photonics 5, no. 4, 1539-1545 (2018)
Résumé: © 2018 American Chemical Society. Near-field scanning optical microscopy (NSOM) achieves subwavelength resolution by bringing a nanosized probe close to the surface of the sample. This extends the spectrum of spatial frequencies that can be detected with respect to a diffraction limited microscope. The interaction of the probe with the sample is expected to affect its radiation to the far field in a way that is often hard to predict. Here we address this question by proposing a general method based on full-field off-axis digital holography microscopy which enables to study in detail the far-field radiation from a NSOM probe as a function of its environment. A first application is demonstrated by performing a three-dimensional (3D) tomographic reconstruction of light scattered from the subwavelength aperture tip of a NSOM, in free space or coupled to transparent and plasmonic media. A single holographic image recorded in one shot in the far field contains information on both the amplitude and the phase of the scattered light. This is sufficient to reverse numerically the propagation of the electromagnetic field all the way to the aperture tip. Finite Difference Time Domain (FDTD) simulations are performed to compare the experimental results with a superposition of magnetic and electric dipole radiation.
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Far-field to near-field investigation of thermal radiation emitted by a single optical nanoantenna
Li, C., V. Krachmalnicoff, P. Bouchon, J. Jaeck, N. Bardou, R. Haidar, and Y. De Wilde
Progress in Electromagnetics Research Symposium 2018-November, 2473-2478 (2018)
Résumé: © 2018 Electromagnetics Academy. All rights reserved. Nanoantennas have the ability to spatially and spectrally manipulate light at the nanoscale. Arranged in arrays, they create metasurfaces with homogeneous optical properties but periodicity and coupling between nanoantennas can be detrimental to the study of their intrinsic optical response. In order to investigate the electromagnetic properties of a single nanoantenna, we use a set-up based on thermal radiation scanning tunneling microscopy (TRSTM) to characterize an isolated nanoantenna from the near field to the far field by achieving sub-wavelength imaging in the mid-infrared.
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Correlated blinking of fluorescent emitters mediated by single plasmons
Bouchet, D., E. Lhuillier, S. Ithurria, A. Gulinatti, I. Rech, R. Carminati, Y. De Wilde, and V. Krachmalnicoff
Physical Review A - Atomic, Molecular, and Optical Physics 95, no. 3 (2017)
Résumé: © 2017 American Physical Society.We observe time-correlated emission between a single CdSe/CdS/ZnS quantum dot exhibiting single-photon statistics and a fluorescent nanobead located micrometers apart. This is accomplished by coupling both emitters to a silver nanowire. Single plasmons are created on the latter from the quantum dot, and transfer energy to excite in turn the fluorescent nanobead. We demonstrate that the molecules inside the bead show the same blinking behavior as the quantum dot.
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Enhancement and Inhibition of Spontaneous Photon Emission by Resonant Silicon Nanoantennas
Bouchet, D., M. Mivelle, J. Proust, B. Gallas, I. Ozerov, M. F. Garcia-Parajo, A. Gulinatti, I. Rech, Y. De Wilde, N. Bonod, V. Krachmalnicoff, and S. Bidault
Physical Review Applied 6, no. 6 (2016)
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Near-field to far-field characterization of speckle patterns generated by disordered nanomaterials
Parigi, V., E. Perros, G. Binard, C. Bourdillon, A. Maitre, R. Carminati, V. Krachmalnicoff, and Y. De Wilde
Optics Express 24, no. 7, 7019-7027 (2016)
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Long-Range Plasmon-Assisted Energy Transfer between Fluorescent Emitters
Bouchet, D., D. Cao, R. Carminati, Y. De Wilde, and V. Krachmalnicoff
Physical Review Letters 116, no. 3 (2016)
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Mapping the radiative and the apparent nonradiative local density of states in the near field of a metallic nanoantenna
Cao, D., A. Cazé, M. Calabrese, R. Pierrat, N. Bardou, S. Collin, R. Carminati, V. Krachmalnicoff, and Y. De Wilde
ACS Photonics 2, no. 2, 189-193 (2015)
Résumé: © 2015 American Chemical Society. We present a novel method to extract the various contributions to the photonic local density of states from near-field fluorescence maps. The approach is based on the simultaneous mapping of the fluorescence intensity and decay rate and on the rigorous application of the reciprocity theorem. It allows us to separate the contributions of the radiative and the apparent nonradiative local density of states to the change in the decay rate. The apparent nonradiative contribution accounts for losses due to radiation out of the detection solid angle and to absorption in the environment. Data analysis relies on a new analytical calculation, and does not require the use of numerical simulations. One of the most relevant applications of the method is the characterization of nanostructures aimed at maximizing the number of photons emitted in the detection solid angle, which is a crucial issue in modern nanophotonics.
Mots-clés: fluorescence microscopy; local density of states; near-field scanning probe; plasmonic nanoantennas; radiative decay rate; reciprocity theorem
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Electromagnetic density of states in complex plasmonic systems
Carminati, R., A. Cazé, D. Cao, F. Peragut, V. Krachmalnicoff, R. Pierrat, and Y. De Wilde
Surface Science Reports 70, no. 1, 1-41 (2015)
Résumé: © 2014 Elsevier B.V. All rights reserved. Nanostructured materials offer the possibility to tailor light-matter interaction at scales below the wavelength. Metallic nanostructures benefit from the excitation of surface plasmons that permit light concentration at ultrasmall length scales and ultrafast time scales. The local density of states (LDOS) is a central concept that drives basic processes of light-matter interaction such as spontaneous emission, thermal emission and absorption. We introduce theoretically the concept of LDOS, emphasizing the specificities of plasmonics. We connect the LDOS to real observables in nanophotonics, and show how the concept can be generalized to account for spatial coherence. We describe recent methods developed to probe or map the LDOS in complex nanostructures ranging from nanoantennas to disordered metal surfaces, based on dynamic fluorescence measurements or on the detection of thermal radiation.
Mots-clés: Cross density of states; Local density of states; Plasmonics; Spatial coherence; Spontaneous emission; Thermal radiation
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Towards a full characterization of a plasmonic nanostructure with a fluorescent near-field probe
Krachmalnicoff, V., D. Cao, A. Cazé, E. Castanié, R. Pierrat, N. Bardou, S. Collin, R. Carminati, and Y. De Wilde
Optics Express 21, no. 9, 11536-11545 (2013)
Résumé: We report on the experimental and theoretical study of the spatial fluctuations of the local density of states (EM-LDOS) and of the fluorescence intensity in the near-field of a gold nanoantenna. EM-LDOS, fluorescence intensity and topography maps are acquired simultaneously by scanning a fluorescent nanosource grafted on the tip of an atomic force microscope at the surface of the sample. The results are in good quantitative agreement with numerical simulations. This work paves the way for a full near-field characterization of an optical nanoantenna. © 2013 Optical Society of America.
Mots-clés: Atomic force microscope (AFM); Fluorescence intensities; Local density of state; Near-field characterizations; Optical nano antennas; Plasmonic nanostructures; Quantitative agreement; Spatial fluctuation; Atomic force microscopy; Nanostructures; Surface topography; Fluorescence
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Distance dependence of the local density of states in the near field of a disordered plasmonic film
Castanié, E., V. Krachmalnicoff, A. Cazé, R. Pierrat, Y. De Wilde, and R. Carminati
Optics Letters 37, no. 14, 3006-3008 (2012)
Résumé: We measure the statistical distribution of the photonic local density of states in the near field of a semicontinuous gold film. By varying the distance between the measurement plane and the film, we show that near-field confined modes play a major role in the width of the distribution. Numerical simulations in good agreement with experiments allow us to point out the influence of nonradiative decay channels at short distance. © 2012 Optical Society of America.
Mots-clés: Confined modes; Gold film; Local density of state; Measurement planes; Near fields; Near-field; Nonradiative decay channels; Plasmonic; Semi-continuous; Statistical distribution; Optics; Optoelectronic devices
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Enhanced light-matter interaction at the nanoscale using localized plasmon modes on disordered metallic films
Carminati, R., E. Castanié, V. Krachmalnicoff, A. Cazé, R. Pierrat, and Y. De Wilde
2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011 (2011)
Résumé: Disordered semi-continuous metallic films are a particularly striking example of complex photonic systems. They exhibit peculiar optical properties that cannot be explained from the behavior of bulk metals or ensembles of isolated nanoparticles [1]. The interplay between surface-plasmon excitations and scattering by multiscale (fractal) metallic clusters leads to spatial localization of the electromagnetic field in subwavelength areas (hot spots). A feature of these hot-spots modes is the expected coexistence of both localized and delocalized modes at the same frequency [2,3], a situation referred to as inhomogeneous localization. © 2011 IEEE.
Mots-clés: Bulk metals; Hot spot; Hotspots; Light-matter interactions; Metallic clusters; Multiscales; Nano scale; Photonic systems; Plasmon modes; Semi-continuous; Spatial localization; Sub-wavelength; Surface plasmon excitation; Electromagnetic fields; Electron optics; Metallic films; Optical properties; Optics; Quantum electronics; Plasmons
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Sub-poissonian number differences in four-wave mixing of matter waves
Jaskula, J.-C., M. Bonneau, G. B. Partridge, V. Krachmalnicoff, P. Deuar, K. V. Kheruntsyan, A. Aspect, D. Boiron, and C. I. Westbrook
Physical Review Letters 105, no. 19 (2010)
Résumé: We demonstrate sub-Poissonian number differences in four-wave mixing of Bose-Einstein condensates of metastable helium. The collision between two Bose-Einstein condensates produces a scattering halo populated by pairs of atoms of opposing velocities, which we divide into several symmetric zones. We show that the atom number difference for opposing zones has sub-Poissonian noise fluctuations, whereas that of nonopposing zones is well described by shot noise. The atom pairs produced in a dual number state are well adapted to sub-shot-noise interferometry and studies of Einstein-Podolsky-Rosen-type nonlocality tests. © 2010 The American Physical Society.
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Fluctuations of the local density of states probe localized surface plasmons on disordered metal films
Krachmalnicoff, V., E. Castanié, Y. De Wilde, and R. Carminati
Physical Review Letters 105, no. 18 (2010)
Résumé: We measure the statistical distribution of the local density of optical states (LDOS) on disordered semicontinuous metal films. We show that LDOS fluctuations exhibit a maximum in a regime where fractal clusters dominate the film surface. These large fluctuations are a signature of surface-plasmon localization on the nanometer scale. © 2010 The American Physical Society.
Mots-clés: Disordered metals; Film surfaces; Fractal clusters; Local density; Local density of state; Localized surface plasmon; Nano-meter scale; Optical state; Semicontinuous metal films; Statistical distribution; Surface-plasmon; Metallic films; Plasmons; Optical data storage
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