A5073026886- Gold and Silver Nanoparticles Synthesis and Applications
- Plasmonic and Surface Plasmon Research
- Nonlinear Optical Materials Studies
- Thermal Radiation and Cooling Technologies
- Thermal properties of materials
- Mechanical and Optical Resonators
- Photoacoustic and Ultrasonic Imaging
- nanoparticles nucleation surface interactions
- Nanopore and Nanochannel Transport Studies
- Force Microscopy Techniques and Applications
- Carbon Nanotubes in Composites
- Near-Field Optical Microscopy
- Quantum Dots Synthesis And Properties
- Spectroscopy Techniques in Biomedical and Chemical Research
- Protein Interaction Studies and Fluorescence Analysis
- Advanced Thermodynamics and Statistical Mechanics
- Spectroscopy and Quantum Chemical Studies
- Microfluidic and Bio-sensing Technologies
- DNA and Nucleic Acid Chemistry
- Advanced biosensing and bioanalysis techniques
- Thermography and Photoacoustic Techniques
- Laser-Ablation Synthesis of Nanoparticles
- Cancer therapeutics and mechanisms
- Ultrasound and Cavitation Phenomena
- Orbital Angular Momentum in Optics
Université Claude Bernard Lyon 1
2016-2025
Centre National de la Recherche Scientifique
2016-2025
Institut Lumière Matière
2016-2025
Laboratoire de Spectrométrie Ionique et Moléculaire
2008-2012
École Normale Supérieure - PSL
2009
Delft University of Technology
2007-2008
Laboratoire Kastler Brossel
2003-2005
Sorbonne Université
2003-2005
The ultrafast optical nonlinearity of an optically characterized single gold nanorod is investigated around its surface plasmon resonance, by combining a far-field spatial modulation technique with high sensitivity pump-probe setup. spectrally and temporally dependent response quantitatively interpreted in terms the bulklike enhanced plasmonic effect. resonance dynamics shown to be mostly governed nonequilibrium electron phonon processes. Their contributions nonlinear metal nano-object are...
The optical extinction spectra of single silver nanoparticles coated with a silica shell were investigated in the size range 10−50 nm. Measurements performed using spatial modulation spectroscopy technique which permits independent determination both metal nanoparticle under study and width its localized surface plasmon resonance (LSPR). These parameters can thus be directly correlated at particle level for first time. results show linear increase LSPR inverse diameter small regime (less...
The dependence of the spectral width longitudinal localized surface plasmon resonance (LSPR) individual gold nanorods protected by a silica shell is investigated as function their size. Experiments were performed using spatial modulation spectroscopy technique that permits determination both characteristics LSPR an nanoparticle and its morphology. measured shown to broaden with reduction nanorod length diameter, which in contrast predictions existing classical quantum theoretical models....
The acoustic response of surface-controlled metal (Pt) nanoparticles is investigated in the small size range, between 1.3 and 3 nm (i.e., 75−950 atoms), using time-resolved spectroscopy. Acoustic vibration demonstrated, with frequencies ranging from 1.1 to 2.6 THz, opening way development THz resonators. frequencies, measured a noncontact optical method, are excellent agreement prediction macroscopic approach based on continuous elastic model, together bulk material constants. This...
Hybrid nano-objects formed by two or more disparate materials are among the most promising and versatile nanosystems. A key parameter in their properties is interaction between components. In this context we have investigated ultrafast charge separation semiconductor–metal nanohybrids using a model system of gold-tipped CdS nanorods matchstick architecture. Experiments performed an optical time-resolved pump–probe technique, exciting either semiconductor metal component particles, probing...
The impact of quantum confinement on the width surface plasmon resonance a metal nanoparticle is theoretically investigated in model system formed by silver nanosphere different environments. Calculations are performed using time-dependent local density approximation (TDLDA) for diameters up to about 11 nm, permitting precise quantification broadening due size reduction. As expected, this found be inversely proportional particle diameter, but with an amplitude strongly depending environment...
The cooling dynamics of glass-embedded noble metal nanoparticles with diameters ranging from 4 to 26 nm were studied using ultrafast pump-probe spectroscopy. Measurements performed probing away the surface plasmon resonance avoid spurious effects due glass heating around particle. In these conditions, time-domain data reflect kinetics nanoparticle. Cooling are shown be controlled by both thermal resistance at nanoparticle-glass interface and heat diffusion in matrix. Moreover, conductances...
The optical extinction response of individual Au-Ag@SiO2 heterodimers whose morphologies are determined by transmission electron microscopy (TEM) is investigated using spatial modulation spectroscopy. spectra show two resonances spectrally close to the surface plasmon constituting Au and Ag@SiO2 core-shell particles. interparticle electromagnetic coupling demonstrated induce a large increase dimer around its Au-like resonance for light polarized along axis, as compared that perpendicular...
The lifetimes of the acoustic vibrations metal nanostructures depend sensitively on properties environment, such as impedance and viscosity. In order to accurately study these effects, they have be separated from damping processes that are inherent nanostructure. Here we show this can done experimentally by investigating individual gold nanowires suspended over a trench in air liquid environments. experiments were ultrafast pump-probe microscopy, recording transient absorption traces at same...
The spectral characteristics (wavelength and line width) the optical extinction cross-section of longitudinal localized surface plasmon resonance (LSPR) individual gold nanobipyramids have been quantitatively measured using spatial modulation spectroscopy technique. morphology same nanoparticles has determined by transmission electron microscopy (TEM). experimental results are thus interpreted with a numerical model TEM sizes particles as an input, either including substrate or assuming mean...
Acoustic vibrations of small nanoparticles are still ruled by continuum mechanics laws down to diameters a few nanometers. The elastic behavior at lower sizes (<1–2 nm), where become molecular clusters made tens atoms, is little explored. question remains which extent the transition from continuous-mass solids discrete-atom affects their specific low-frequency vibrational modes, whose period classically expected linearly scale with diameter. Here, we investigate experimentally ultrafast...
The dynamics of supercoiled DNA play an important role in various cellular processes such as transcription and replication that involve supercoiling. We present experiments enhance our understanding these by measuring the intrinsic response single molecules to sudden changes tension or torsion. observed can be accurately described quasistatic models, independent degree supercoiling initially molecules. In particular, are not affected continuous removal plectonemes. These results set upper...
Functional cluster-assembled nanostructures with original structures and properties are prepared using the Low Energy Cluster Beam Deposition method (LECBD). This technique consists in depositing supersonic clusters produced gas phase a combined laser vapourisation-inert condensation source. energy typical sizes ranging from ∼1 to few nm not fragmented upon impact on substrate (soft landing regime) leading formation of which retain incident free clusters. Model nanostructured systems any...
Knowledge of the vibrational spectrum metal clusters and nanoparticles is fundamental interest since it a signature their morphology, can be used to determine mechanical, thermodynamical, other physical properties. It expected that such depends on material, size, shape nanoparticles. In this work, we report spectra density states Au, Pt, Ag in size range 0.5–4 nm (13–2057 atoms), with icosahedral, Marks decahedral, FCC morphologies. The were calculated through atomistic simulations...
The effects of the dielectric environment on optical extinction spectra gold nanorods were quantitatively studied using individual bare and silica-coated nanorods. dispersion amplitude their cross-section, dominated by absorption for investigated sizes, measured spatial modulation spectroscopy (SMS). experimental results compared to calculations from a numerical model that included environmental features present in measurements morphology size corresponding transmission electron microscopy....
Acoustic vibrations of assemblies gold nanoparticles were investigated using ultralow frequency micro-Raman scattering and finite element simulations. When exciting the resonantly with surface plasmon resonance electromagnetically coupled nanoparticles, Raman spectra present an band whose lies below lowest active Lamb mode single that was observed. This feature ascribed to a vibration nanoparticle "supermolecules", is, mechanically by surrounding polymer molecules. Its measured is inversely...
Tunable two-color ultrafast pump–probe experiments are performed on colloidal metal nanospheres in water and ethanol, the results interpreted through a model including thermal dynamics both nanoparticle its environment. Transient optical signals measured for gold nanoparticles ethanol display complex temporal response strongly dependent wavelength of probe beam. We demonstrate that origin is related to large contribution liquid environment transient heating response, contrast usual...
Observation of DNA–protein interactions by single molecule fluorescence microscopy is usually performed using fluorescent DNA binding agents. However, such dyes have been shown to induce cleavage the and perturb its with proteins. A new method for detection surface-attached molecules introduced in this paper. Biotin- and/or digoxigenin-modified fragments are covalently linked at both extremities a via sequence-specific hybridization ligation. After modified stretched on glass surface, their...
The impact of spherical symmetry breaking and crystallinity on the response vibrational acoustic modes a nanoobject in frequency- time-domain experiments is investigated using finite-element analysis method. results show that introduction shape anisotropy, i.e., evolution from nanosphere to nanorod, modifies periods fundamental radial quadrupolar leads activation quadrupolar-like mode studies. In contrast, shown have negligible breathing frequency formed by cubic crystal does not activate...
The acoustic vibrations of metal nanoparticles encapsulated in a dielectric shell (Ag@SiO2) were investigated using time-resolved femtosecond technique. measured vibration periods significantly differ from those predicted for the bare cores and, depending on relative core and sizes, found to be either larger or smaller than them. These results show that whole core–shell particle is excited detected. Moreover, vibrational are excellent agreement with predictions model based continuum...