A5084510039- Magnetism in coordination complexes
- Photoacoustic and Ultrasonic Imaging
- Mechanical and Optical Resonators
- Electron Spin Resonance Studies
- Laser Material Processing Techniques
- Solid-state spectroscopy and crystallography
- Force Microscopy Techniques and Applications
- Organic and Molecular Conductors Research
- Ultrasonics and Acoustic Wave Propagation
- X-ray Diffraction in Crystallography
- Chemical Thermodynamics and Molecular Structure
- Lanthanide and Transition Metal Complexes
- Nonlinear Optical Materials Studies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Magnetic Properties and Applications
- Photoreceptor and optogenetics research
- Liquid Crystal Research Advancements
- Shape Memory Alloy Transformations
- Thermography and Photoacoustic Techniques
- Crystal structures of chemical compounds
- Acoustic Wave Resonator Technologies
- Corrosion Behavior and Inhibition
- Magnetic properties of thin films
- Spectroscopy and Quantum Chemical Studies
- Thermal Radiation and Cooling Technologies
Institut de Physique de Rennes
2021-2024
Centre National de la Recherche Scientifique
2017-2024
Université de Rennes
2024
The University of Tokyo
2024
Massachusetts Institute of Technology
2020-2023
Institut des Molécules et Matériaux du Mans
2016-2021
Le Mans Université
2016-2021
Institut des Matériaux Jean Rouxel
2021
Institute for Soldier Nanotechnologies
2021
Abstract Ultrafast photoinduced phase transitions at room temperature, driven by a single laser shot and persisting long after stimuli, represent emerging routes for ultrafast control over materials’ properties. Time-resolved studies provide fundamental mechanistic insight into far-from-equilibrium electronic structural dynamics. Here we study the transformation of Rb 0.94 Mn Co 0.06 [Fe(CN) 6 ] 0.98 material, designed to exhibit 75 K wide thermal hysteresis around temperature between III Fe...
Abstract The ability to generate efficient giga–terahertz coherent acoustic phonons with femtosecond laser makes acousto-optics a promising candidate for ultrafast light processing, which faces electronic device limits intrinsic complementary metal oxide semiconductor technology. Modern acousto-optic devices, including optical mode conversion process between ordinary and extraordinary waves (and vice versa), remain limited the megahertz range. Here, using generated at tens of gigahertz...
A number of nascent coating and micromanufacturing processes involve particles sprayed at a high velocity, which impact substrate, deform, adhere. Successful bonding between the substrate requires velocities higher than so-called critical adhesion velocity. This velocity is influenced by temperature variable that we isolate in this work conducting single-particle impacts on variable-temperature for three systems (Al–Al, Sn–Sn, Ti–Ti) with individually selected within narrow size...
We present an optical technique based on ultrafast photoacoustics to precisely determine the local temperature distribution profile in liquid samples contact with a laser heated transducer. This pump-probe experiment uses time-domain Brillouin scattering (TDBS) locally light frequency shift. As influences frequency, TDBS signal probes laser-induced liquid. demonstrate relevance and sensitivity of this for measurement absolute gradient glass forming prototype, glycerol, at different pump...
Absorption of ultrashort laser pulses in a metallic grating deposited on transparent sample launches coherent compression/dilatation acoustic directions different orders diffraction. Their propagation is detected by delayed pulses, which are also diffracted the grating, through measurement transient intensity change first-order light. The obtained data contain multiple frequency components, interpreted considering all possible angles for Brillouin scattering light achieved multiplexing and...
We demonstrate that time-domain Brillouin scattering (TDBS), a technique based on an ultrafast pump-probe approach, is sensitive to phase transitions and apply it the study of structural changes in 8CB liquid crystals at different temperatures across isotropic, nematic, smectic, crystalline phases. investigate viscoelastic properties squeezed narrow gap, from nanometer submicrometer thickness range, conclude long-range molecular structuring smectic phase. These TDBS results reveal...
Pulsed lasers are routinely used to optically excite and detect ultrasounds in a broad frequency range, from megahertz terahertz. Though well-established for decades, this technique of laser ultrasonics is constrained by the potential optical damage it may cause sample, resulting generation relatively weak pressures, well below kilobars. This study introduces methodology excitation nondestructive shock waves, at high repetition rate, limited only mechanical strength sample. work establishes...
We report GHz longitudinal as well shear acoustic phonon photoexcitation and photodetection using femtosecond laser pulses in a spin-crossover molecular crystal. From our experimental observation of time domain Brillouin scattering triggered by the waves across low-spin (LS) to high-spin (HS) thermal crossover, we reveal link between spin state coherent phonons. In particular, experimentally evidence non-thermal pathway for excitation also provide insights into optical mechanical parameters...
Herein we describe a novel spinning pump-probe photoacoustic technique developed to study nonlinear absorption in thin films. As test case, an organic polycrystalline film of quinacridone, well-known pigment, with thickness the tens nanometers range, is excited by femtosecond laser pulse which generates time-domain Brillouin scattering signal. This signal directly related strain wave launched from into substrate and can be used quantitatively extract optical properties itself. Quinacridone...
Abstract The Rb 0.94 Mn Co 0.06 [Fe(CN) 6 ] 0.98 material was designed to exhibit a 75 K wide thermal hysteresis around room temperature, associated with bistability between the low temperature III Fe II tetragonal phase and high cubic phase. We have recently shown that single laser pulse can be used drive, at photoinduced transition from By using specific powder sample streaming technique, we could monitor by time‐resolved X‐ray diffraction how ultrafast out‐of‐equilibrium dynamics, imposed...
We report GHz longitudinal as well shear acoustic phonons photoexcitation and photodetection using femtosecond laser pulses in a spin-crossover molecular crystal. From our experimental observation of time domain Brillouin scattering triggered by the waves across low-spin (LS) to high-spin (HS) thermal crossover, we reveal link between spin state coherent phonons. In particular, experimentally evidence an unconventional non-thermal pathway for excitation also provide insight on optical...
The laser ultrasonics technique perfectly fits the needs for non-contact, non-invasive, non-destructive mechanical probing of samples mm to nm sizes. This is however limited excitation low-amplitude strains, below threshold optical damage sample. In context strain engineering materials, alternative techniques enabling high amplitude strains in a regime are seeking. We introduce here method laser-shock wave generation based on additive superposition multiple laser-excited waves. enables up...
We present results of time-domain Brillouin scattering (TDBS) to determine the local temperature liquids in contact an optical transducer. TDBS is based on ultrafast pump-probe technique light frequency shift caused by propagation coherent acoustic waves a sample. Since influences shift, signal probes liquid. Results for extracted frequencies recorded at different liquid temperatures and laser powers - i.e. steady state background temperatures- are shown demonstrate usefulness as probe. This...
Herein we describe a novel spinning pump-probe photoacoustic technique developed to study nonlinear absorption in thin films. As test case, an organic polycrystalline film of quinacridone, well-known pigment, with thickness the tens nanometers range, is excited by femtosecond laser pulse which generates time-domain Brillouin scattering signal. This signal directly related strain wave launched from into substrate and can be used quantitatively extract optical properties itself. Quinacridone...