A5079737569- Gold and Silver Nanoparticles Synthesis and Applications
- Mechanical and Optical Resonators
- Laser-Plasma Interactions and Diagnostics
- Plasmonic and Surface Plasmon Research
- Terahertz technology and applications
- Laser-Matter Interactions and Applications
- Advanced X-ray Imaging Techniques
- Nonlinear Optical Materials Studies
- Acoustic Wave Resonator Technologies
- Multiferroics and related materials
- nanoparticles nucleation surface interactions
- Advanced Chemical Physics Studies
- Topological Materials and Phenomena
- Ultrasonics and Acoustic Wave Propagation
- Thermal properties of materials
- Quantum, superfluid, helium dynamics
- Geophysics and Sensor Technology
- Spectroscopy and Quantum Chemical Studies
- Physics of Superconductivity and Magnetism
- High-pressure geophysics and materials
- X-ray Spectroscopy and Fluorescence Analysis
- Near-Field Optical Microscopy
- X-ray Diffraction in Crystallography
- Nuclear Physics and Applications
- Laser Material Processing Techniques
Institut des Molécules et Matériaux du Mans
2017-2025
Le Mans Université
2017-2025
Centre National de la Recherche Scientifique
2011-2023
University of Silesia in Katowice
2020
Université Claude Bernard Lyon 1
2008-2016
Institut Lumière Matière
2013-2016
Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy
2013-2015
Laboratoire de Spectrométrie Ionique et Moléculaire
2010-2012
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...
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 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....
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...
The acoustic vibration modes of spherical composite nanoparticles formed by a core and an arbitrary number shells are computed using semianalytic approach based on elastic theory. observed in time-resolved pump-probe experiments identified the case metal-dielectric-based nanoparticles, results illustrated Ag@SiO${}_{2}$ core-shell nanoparticles. presence light dielectric shell is shown to only weakly shift frequency dominant mode experiments. Moreover, large impact mechanical contact between...
Ultrashort light pulses induce rapid deformations of crystalline lattices. In ferroelectrics, lattice couple directly to the polarization, which opens perspective modulate electric polarization on an ultrafast time scale. Here, we report temporal and spatial tracking strain polar modulation in a single-domain BiFeO3 thin film by ultrashort pulses. To map light-induced deformation unit cell, perform time-resolved optical reflectivity x-ray diffraction. We show that femtosecond laser pulse...
The transient electronic and molecular structure arising from photoinduced charge transfer in transition metal complexes is studied by X-ray powder diffraction with a 100 fs temporal atomic spatial resolution. Crystals containing dense array of Fe(II)-tris(bipyridine) ([Fe(bpy)3](2 +)) their [Formula: see text] counterions display pronounced changes electron density that occur within the first after two-photon excitation small fraction [Fe(bpy)3](2 +) complexes. Transient maps derived data...
We study the quasi-instantaneous change of electron density in unit cells LiH and NaBH4 response to a nonresonant strong optical field. determine for first time related transient maps, applying femtosecond x-ray powder diffraction as structure probe. The light-induced charge relocation exhibits an transfer from anion (BH(4)(-)) Na(+) cation. In contrast, displays opposite behavior, i.e., increase ionicity presence electric This behavior originates correlations LiH, is evident comparison with...
Superlattices are materials created by the alternating growth of two chemically different materials. The direct consequence creating a superlattice is folding Brillouin zone, which gives rise to additional electronic bands and phonon modes. This phenomenon has been successfully exploited achieve new transport optical properties in semiconductor superlattices. Here, we show that multiferroic BiFeO3/LaFeO3 superlattices exhibit several structural orders parallel perpendicular direction, not...
In this paper, we develop a method that combines optical birefringence properties and time-domain Brillouin scattering microscopy to determine in situ the axis orientation of each single micrometer size grain polycrystalline sample. We illustrate by investigating room temperature multiferroic material BiFeO3 where coincides with ferroelectric polarization direction. are able find also provide sound velocity (longitudinal transverse) since is based on process. These advances open interesting...
Density Functional Theory (DFT) calculations not only allow to predict the vibrational and optical properties of solids but also understand disentangle mechanisms playing a key role in generation coherent phonons. Recent experiments performed on Bi$_2$Te$_3$ nanofilm have shown that THz pulse launches at least $A_{1g}^1$ phonon as transient transmittance measured using an isotropic detection scheme displays oscillations with frequency matching mode Raman experiments. Such observation can be...
The temperature dependence of the thermal boundary resistivity is investigated in glass-embedded Ag particles radius 4.5 nm, range from 300 to 70 K, using all-optical time-resolved nanocalorimetry. present results provide a benchmark for theories aiming at explaining interface between metal nanoparticles and their environment, topic great relevance when tailoring energy delivery as applications nanomedicine management nanoscale
Elaborating advanced nanomaterials based on the assembly of nanoparticles (NPs) is a versatile route for targeting and tuning wide variety properties like optical, magnetic, electrical or sensing. This usually employs so-called soft chemistry which has advantage being quite cheap transferable to an industrial level. However, getting quantitative information quality mechanical consolidation nanoparticle (ordered disordered) in nondestructive manner not often achieved, although it crucial...
The interaction of intense femtosecond pulses with metals allows for generating ultrashort hard x-rays. In contrast to plasma theories, tunneling from the target into vacuum is introduced as electron generation step, followed by acceleration in laser field and re-entrance generate characteristic x-rays Bremsstrahlung. For negligible space charge vacuum, Kα flux proportional incident intensity wavelength squared, suggesting a strong enhancement x-ray mid-infrared driving pulses. This...
We report the generation of coherent acoustic phonons in materials with terahertz ultrashort pulses. This is demonstrated metals and topological insulators by exciting an eigenmode nanometric-sized thin films. The efficiency coupling quadratic electric field strength within range investigation. Owing to a quantitative comparison between near-infrared pulse excitations, we show that process phonon radiation mainly driven thermoelastic stress. While for light excitation lattice temperature...
Linear and nonlinear magneto-photonic properties of periodic arrays nickel nanodimers are governed by the interplay (local) optical response individual nanoparticles (non-local) diffraction phenomena, with a striking example Wood's anomaly. Angular magnetic-field dependencies second harmonic intensity evidence anomaly when new orders emerge. Near-infrared spectroscopic measurements performed at different wavelengths grating constants discriminate between linear excitation mechanisms...
X-Ray diffraction provides insight into the distribution of electronic charge in crystals. Equilibrium electron distributions have been determined with high spatial resolution by recording and analysing a large number peaks under stationary conditions. In contrast, transient densities during after structure-changing processes are mainly unknown. Recently, we introduced femtosecond X-ray powder from polycrystalline samples to determine density maps 0.03 nm temporal 100 fs. pump–probe approach...
Enabling the light-control of complex systems on ultra-short timescales gives rise to rich physics with promising applications. While crucial, quantitative determination both longitudinal and shear photo-induced strains still remains challenging. Here, by scrutinizing asymmetric Bragg peaks pairs $(\pm h01)$ using picosecond time-resolved X-ray diffraction experiments in BiFeO$_3$, we simultaneously determine strains. The relative amplitude those can be explained only if thermal non-thermal...
Clear anomalies in the lattice thermal expansion (deviation from linear variation) and elastic properties (softening of sound velocity) at antiferromagnetic-to-paramagnetic transition are observed prototypical multiferroic BiFeO3 using a combination picosecond acoustic pump-probe high-temperature X-ray diffraction experiments. Similar also evidenced first-principles calculations supporting our experimental findings. Those addition to simple Landau-like model we developed allow understand...
Mechanisms of spin/charge interconversion like the spin Hall effect can be used to generate and detect currents at timescales ranging from dc subpicosecond. In regime, best candidates are Rashba interfaces showing inverse Edelstein effect, with ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ presenting a record conversion efficiency. At picosecond timescales, devices relying on efficient THz emitters, but this is less clear for Rashba-Edelstein systems. Here we study angular momentum into charge...
The spectral response of metallic nanoparticles is dominated by the Localized Surface Plasmon Resonance (LSPR). While its position well understood, measuring and interpreting LSPR linewidth evolution with shape size still an important issue for both fundamental investigations applications. It needs use single particle experiments on a controlled environment, to avoid inhomogeneous broadening and/or spurious effects. dominant effect related reduction increase surface contribution LSPR, due...
Spin/charge interconversion mechanisms provide an essential handle to generate and detect spin currents. Their applications at different timescales are critical in spintronics since they cover a technologically relevant broadband spectrum. While the inverse Hall effect is known be robust from quasi-static sub-picosecond timescales, conversion efficiency evolution of Edelstein has not been addressed yet. In this work, we report that while response can comparable most efficient systems,...