arXiv subjects

Thomas Dehoux

Publications and source records attributed to Thomas Dehoux.

4 recordsLinked to original sources

arXiv2026

Resonant attenuation of surface acoustic waves by a weakly bonded layer

We investigate the propagation of surface acoustic waves (SAWs) in a layered half-space system comprising a continuous, sub-wavelength-thick layer weakly adhering to a substrate. Using finite element simulations, we demonstrate that this configuration - without requiring surface structuration - gives rise to frequency ranges bounded in k-space and characterized by strong SAW attenuation, which we term adhesion-induced resonant attenuation zones. We show that these attenuation zones closely mimic the resonant behavior typically observed in locally resonant metamaterials and can be understood through a mass-spring analogy, where the adhesion between the layer and substrate governs the frequency and width of the attenuation zones. As a practical demonstration, we propose a bilayer configuration as a practical route to experimentally realize adhesion-induced resonant attenuation of SAWs, where a soft and thin interfacial film serves as an intermediate adhesive bonding between the layer and substrate, providing a realistic and tunable interfacial stiffness. Our findings offer a simplified route to achieving SAW manipulation through continuous layered media with tunable adhesion, providing a practical alternative to complex structural designs in SAW-based devices across a broad frequency range.

physics.app-ph↗

arXiv2025

Separating water content from network dynamics in cell nuclei with Brillouin microscopy

Probing forces, deformations and generally speaking the mechanical properties of cells is the hallmark of mechanobiology. In the last two decades many techniques have been developed to this end that are largely based on deforming the cells and measuring the reaction force. In cells, an alternative approach has been implemented mid 2010's, based on Brillouin Light Scattering (BLS) that produces a spectrum that can be interpreted as the response of the sample to an infinitesimal uniaxial compression at picosecond timescales. In all of these measurements, the response of the cell is quantified with a colloquial "stiffness" that encompasses both the contribution of load-bearing structures and volume changes, much to confusion. To clarify the interpretation of the hypersonic data obtained from BLS spectra, we vary the relative volume fraction of intracellular water and solid network by applying osmotic compressions to single cells. In the nucleus, we observe a non-linear increase in the sound velocity and attenuation with increasing osmotic pressure that we fit to a poroelastic model, providing an estimate of the friction coefficient between the water phase and the network. By comparing BLS data to volume measurements, our approach demonstrates clearly that BLS shift alone is mostly sensitive to water content while the additional analysis of the linewidth allows identifying the contribution of the biopolymer-based network dynamics in living cells.

physics.bio-ph↗

arXiv2024

Consensus Statement on Brillouin Light Scattering Microscopy of Biological Materials

Brillouin Light Scattering (BLS) spectroscopy is a non-invasive, non-contact, label-free optical technique that can provide information on the mechanical properties of a material on the sub-micron scale. Over the last decade it has seen increased applications in the life sciences, driven by the observed significance of mechanical properties in biological processes, the realization of more sensitive BLS spectrometers and its extension to an imaging modality. As with other spectroscopic techniques, BLS measurements not only detect signals characteristic of the investigated sample, but also of the experimental apparatus, and can be significantly affected by measurement conditions. The aim of this consensus statement is to improve the comparability of BLS studies by providing reporting recommendations for the measured parameters and detailing common artifacts. Given that most BLS studies of biological matter are still at proof-of-concept stages and use different--often self-built--spectrometers, a consensus statement is particularly timely to assure unified advancement.

physics.optics↗

arXiv2020

Growing Phenotype-controlled Phononic Materials from Plant Cells Scaffolds

Biological composites offer self-healing properties, biocompatibility, high responsivity to external stimuli, and multifunctionality, due, in part, to their complex, hierarchical microstructure. Such materials can be inexpensively grown, and self-assembled from the bottom up, enabling democratized, sustainable manufacturing routes for micro- and nano-devices. While biological composites have been shown to incorporate rich photonic structures, their phononic properties have hitherto remained unexplored. In this study, we demonstrate that biological composites in the form of micron-thick decellularized onion cell scaffolds behave as an organic phononic material, with the presence of band gaps forbidding the propagation of elastic waves in select frequency ranges. We show that the onion cells' phononic properties can be phenotypically tuned, and anticipate these findings will yield new biologically-derived, "green", and genetically tailorable phononic materials.

physics.app-ph↗