Théorie des ondes (TDO)

Exemple de mode diffus (gauche) et localisé (droit) dans un milieu désordonné corrélé

Figure de speckle au sein d'un milieu désordonné générée numériquement

Réseau désordonné hyperuniforme de points. Une fois habillé par des diffuseurs matériels, cet ensemble présente des propriétés optiques remarquables (transparence, absorption, localisation).

Membres permanents

Rémi CARMINATI

Tél. : 01 80 96 30 72

Marcel FILOCHE

Tél. : 01 80 96 30 82

Arthur GOETSCHY

Tél. : 01 80 96 39 46

Agnès MAUREL

Tél. : 01 80 96 30 71

Pierre MILLIEN

Tél. : 01 80 96 30 51

Romain PIERRAT

Tél. : 01 80 96 30 70

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Actualités

Shearmetry of Fluids with Tunable Rheology by Polarized Luminescence of Rare Earth-Doped Nanorods Wang, Z., Q. Zou, L. Magermans, G. Amselem, C. A. Dessalles, B. Louis, M. Filoche, T. Gacoin, and J. Kim ACS Nano (2024) Résumé: Shear stress plays a critical role in regulating physiological processes within microcirculatory systems. While particle imaging velocimetry is a standard technique for quantifying shear flow, uncertainty near boundaries and low resolution remain severe restrictions. Additionally, shear stress determination is particularly challenging in biofluids due to their significant non-Newtonian behaviors. The present study develops a shearmetry technique in physiological settings using a biomimetic fluid containing rare earth-doped luminescent nanorods acting in two roles. First, they are used as colloidal additives adjusting rheological properties in physiological media. Their anisotropic morphology and interparticle interaction synergistically induce a non-Newtonian shear-thinning effect emulating real biofluids. Second, they can probe shear stress due to the shear-induced alignment. The polarized luminescence of the nanorods allows for quantifying their orientational order parameter and thus correlated shear stress. Using scanning confocal microscopy, we demonstrate the tomographic mapping of the shear stress distribution in microfluidics. High shear stress is evident near the constriction and the cellular periphery, in which non-Newtonian effects can have a significant impact. This emerging shearmetry technique is promising for implementation in physiological and rheological environments of biofluids.
Multiregion Light Control in Diffusive Media via Wavefront Shaping Shaughnessy, L., R. E. Mcintosh, A. Goetschy, C. W. Hsu, N. Bender, H. Yllmaz, A. Yamilov, and H. Cao Physical Review Letters 133, no. 14 (2024) Résumé: Wavefront shaping allows focusing light through or inside strongly scattering media, but the background intensity also increases which reduces the target's contrast. By combining transmission or deposition matrices for different regions, we construct joint operators to achieve spatially resolved control of light in diffusive systems. The eigenmode of a contrast operator can maximize the power contrast between a target and its surrounding. A difference operator enhances the power delivery to a target while avoiding the background increase. This work opens the door to coherent control of nonlocal effects in wave transport for practical applications.
Dispersion and ellipticity of Rayleigh waves in a soil substrate supporting resonant beams and plates Marigo, J. J., K. Pham, A. Maurel, and S. Guenneau Physical Review B 110, no. 9 (2024) Résumé: The behavior of surface waves in a soil supporting an array of beams in three dimensions, or an array of plates in two dimensions, with compressional and flexural resonances is examined both theoretically and numerically. Our findings demonstrate that Love waves, characterized by displacements perpendicular to the sagittal plane, can propagate even without a homogeneous guiding layer, owing to the influence of flexural resonances in beams. Within the sagittal plane, hybridized Rayleigh waves exhibit a dispersion that is notably altered by the presence of the array, with their properties emerging from the interaction between flexural and compressional resonances. Notably, we uncover the coexistence of two Rayleigh waves with distinct wave numbers within specific frequency ranges, corresponding to prograde and retrograde motions. Additionally, both waves significantly amplify ground motion, either horizontally or vertically. Similar physics, yet quantitatively different, is demonstrated in the case of plate arrays.
Characterization and Exploitation of the Rotational Memory Effect in Multimode Fibers Gutiérrez-Cuevas R., , Goetschy A., Bromberg Y., Pelc G., Ravn Andresen E., Bigot L., Quiquempois Y, Bsaibes M, Sillard P., Bigot M., Katz O., De Rosny J., and Popoff S. M. Physical Review X 14, no. 3, 031046 (2024) Résumé: In an ideal perfectly straight multimode fiber with a circular core, the symmetry ensures that rotating the input wave front leads to a corresponding rotation of the output wave front. This invariant property, known as the rotational memory effect (RME), remains independent of the typically unknown output profile. The RME thus offers significant potential for imaging and telecommunication applications. However, in real-life fibers, this effect is degraded by intrinsic imperfections and external perturbations, and is challenging to observe because of its acute sensitivity to misalignments and aberrations in the optical setup. Building on a previously established method for precisely estimating fiber transmission properties, we demonstrate an accurate extraction of RME properties. Additionally, we introduce a comprehensive theoretical framework for both qualitative and quantitative analysis, which specifically links the angular-dependent correlation of the RME to the core deformation’s geometrical properties and the fiber’s mode characteristics. Our theoretical predictions align well with experimental data and simulations for various amounts of fiber distorsion. Finally, we demonstrate the ability to engineer wave fronts with significantly enhanced correlation across all rotation angles. This work enables accurate characterization of distributed disorder from the fabrication process and facilitates calibration-free imaging in multimode fibers. Mots-clés: multimode fiber; wavefront shaping; correlation; memory effect; imaging; telecommunications

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Présentation du thème

Nos activités théoriques (modélisation, approches analytiques et statistiques, simulations numériques) visent à comprendre les propriétés des ondes (optiques, acoustiques, électroniques) dans leurs interactions avec la matière et leur propagation. Ces activités couvrent 3 grandes thématiques : l’étude de systèmes complexes par nature (tissus biologiques, semi-conducteurs désordonnés, fibres multi-modes, cavités chaotiques, réseaux) ; le contrôle de la complexité des matériaux (désordre corrélé, résonance locales, milieux dépendant du temps) ; et le contrôle des ondes (spatial, spectral pour les ondes classiques, nature de l’état pour les ondes quantiques).

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Habib Ammari, Department of Mathematics, ETH Zurich
Geoffroy Aubry, Institut de Physique de Nice
Jean-Philippe Banon, Laboratoire Charles Fabry, Institut d’Optique Graduate School
Élie Bretin, Pôle de Mathématiques, INSA Lyon
Yaron Bromberg, Complex Photonics Lab, The Hebrew University of Jerusalem
CEA DAM
Hui Cao, Hui Cao Research Laboratory, Yale University
Nicolas Cherroret, Complex Quantum Systems, Laboratoire Kastler Brossel
Hilton de Aguiar, Optical imaging in biological and complex media, Laboratoire Kastler Brossel
Aristide Dogariu, Photonics Diagnostics of Random Media, University of Central Florida
Sylvain Gigan, Optical imaging in biological and complex media, Laboratoire Kastler Brossel
Wade Hsu, Optics in Complex Systems, USC
Ori Katz, Advanced Imaging Lab, The Hebrew University of Jerusalem
Fabrice Mortessagne, Institut de Physique de Nice
Sushil Mujumdar Nano-Optics & Mesoscopic Optics Laboratory, TIFR

Vincent Pagneux, LAUM, Le Mans
Philippe Petitjeans, PMMH, ESPCI Paris - PSL
Kim Pham, LMI, ENSTA Paris
Stefan Rotter, Nonlinear dynamics & Complex scattering, Vienna University of Technology
L’Oréal
Saint-Gobain Recherche
Riccardo Sapienza, Complex Nanophotonics, King’s College London
Frank Scheffold, Soft Matter Photonics, University of Fribourg
John Schotland, Department of Mathematics, Yale University
Laurent Seppecher, École Centrale de Lyon
Boris Shapiro, Technion
Simons collaboration on Localization of Waves
Ingve Simonsen, NTNU, Trondheim
Douglas Stone, Department of Applied Physics, Yale University
Nicolas Treps, Quantum Optics group, Laboratoire Kastler Brossel
Damien Vandembroucq, PMMH, ESPCI Paris - PSL
Silvia Vignolini, Max Planck Institute of colloids and interfaces, Potsdam
Kevin Vynck, Institut Lumière Matière, Lyon
Alexey Yamilov, METIS group, MST
Hasan Yılmaz, Bilkent University

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