Samuel Raetz Associate Professor
Institut d'Acoustique–Graduate School (IA–GS), Le Mans Université
Laboratoire d'Acoustique de l'Université du Mans (LAUM, UMR CNRS 6613)Associate Professor in Physical Acoustics at Le Mans Université, I work on laser ultrasonics across MHz–sub-THz frequencies for imaging and characterization of materials, including anisotropic, non-homogeneous, or polycrystalline ones, with applications extending to high-pressure studies in diamond anvil cells.
Science 387(6734): 659-666 (2025)
This paper uses transient grating spectroscopy and picosecond laser ultrasonics, along with simulations, to show that the mantis shrimp’s dactyl club exhibits phononic features (Bloch harmonics, flat dispersion branches, ultraslow modes, and wide Bragg bandgaps in the lower megahertz range) that filter harmful high-frequency stress waves from cavitation bubble collapse, providing effective protection during strikes.
ACS Nano 18(13): 9331-9343 (2024)
This paper demonstrates that cleaved superlattices of (Alx Ga1-x As)/(Aly Ga1-y As) can serve as optically controlled nanotransducers to generate and detect coherent surface and bulk acoustic waves between 40–70 GHz, offering a pathway toward sub-THz coherent nanoacoustics beyond the limits of conventional IDTs and nanopatterned transducers.
The Journal of the Acoustical Society of America 150(3): 2065-2075 (2021)
This paper introduces a semi-analytic multilayer model that sequentially solves the electromagnetic, thermal, and elastodynamic fields involved in laser-generated ultrasound, accounting for optical penetration, heat transport, and interlayer couplings, to efficiently simulate ultrasound generation in complex bonded structures for nondestructive evaluation applications.
Journal of Applied Physics 130(5): 053104 (2021)
This paper shows that time-domain Brillouin scattering enables high-resolution 3D imaging of polycrystalline high-pressure ice in determining grain shape, location, phase, and crystallographic orientation from quasi-longitudinal and quasi-shear coherent acoustic pulse measurements, while simultaneous pulse monitoring across neighboring grains provides a new tool for grain-boundary localization.
Applied Physics Letters 116(10): 104101 (2020)
This paper demonstrates a laser-ultrasonic method using zero-group velocity (ZGV) resonances for nondestructive evaluation of adhesive bonding in trilayer aluminum/epoxy assemblies, showing that resonance attenuation metrics can quantitatively distinguish bond quality and enable 2D imaging of defects.
Physical Review Applied 9(6): 061001 (2018)
This paper demonstrates that laser-generated zero-group velocity (ZGV) Lamb modes can nondestructively track progressive fatigue in aluminum plates, with frequency shifts correlating to fatigue stages and normalized lifetime, enabling damage detection and fatigue-life prediction.
