Acoustofluidics
Acoustic tweezers
The selective precise remote manipulation of micrometric objects both in vivo and vitro open some outstanding perspectives e.g. in medecine for noninvasive surgery, in micro-robotics for microrobots propulsion or in microbiology for cells and microorganisms contactless manipulation, organization and mechanical properties testing. Our team has designed 2 new types of microtweezers: some holographic single beam tweezers based on spiraling interdigitated transducers enabling the precise selective manipulation and organization of microparticles and cells [AT1, AT2, AT3, AT4], and some reconfigurable tweezers based on IDTs arrays and inverse filter enabling real time adative field synthesis [AT5, AT6, AT7].
[AT1] A. Riaud, M. Baudoin, O. Bou Matar, L. Becera, J.-L. Thomas, Selective manipulation of microscopic particles with precursor swirling Rayleigh waves, Phys. Rev. Appl., 7: 024007 (2017)
[AT2] M. Baudoin, J.-C. Gerbedoen, A. Riaud, O. Bou Matar, N. Smagin, J.-L. Thomas, Folding a focalized acoustical vortex on a flat holographic transducer: miniaturized selective acoustical tweezer, Science Advances, 5: eaav1967 (2019)
[AT3] M. Baudoin, J.-L. Thomas, R.A. Sahely, J.C. Gerbedoen, Z. Gong, A. Sivery, O. Bou Matar, N. Smagin, A. Vlandas, Spatialy selective manipulation of cells with single beam acoustical tweezers, Nature Commu., 11: 4244 (2020)
[AT4] Z. Gong, M. Baudoin, Three-dimensional trapping and dynamic axial manipulation with frequency-tuned spiraling acoustical tweezers: A theoretical study, Phys. Rev. Appl., 16: 024034 (2021)
[AT5] A. Riaud, J.L. Thomas, E. Charron, A. Bussonière, O. Bou Matar and M. Baudoin, Anisotropic swirling surface acoustic waves synthesis by inverse filter for on-chip generation of acoustical vortices, Phys. Rev. Appl., 4: 034004 (2015)
[AT6] A. Riaud, J.L. Thomas, M. Baudoin and O. Bou Matar, Taming the degeneracy of Bessel beams at anisotropic-isotropic interface: toward three dimensional control of confined vortical waves, Phys. Rev. E, 92: 063201 (2015)
[AT7] A. Riaud, M. Baudoin, J.-L. Thomas, O. Bou Matar, SAW synthesis with inverse filter and IDTs array: toward a versatile platform for microfluidics and biological applications, IEEE T. Ultrason. Ferr., 63(10): 1601-1607 (2016)
Microstreaming and microswimmers
Inspired by biological microswimmers, many research groups work on artificial microswimmers. Such steerable vessels bear great potential for medical and biological application. Acoustically driven microswimmers have the great advantage of using a biocompatible source decoupled from the moving system. We are studying the most important underlying physical mechanism to the propulsion and control of such swimmers: microstreaming (thus a net flow due to non-linear effects in the fluid) induced around small, oscillating structures. Current efforts concentrate on the streaming flows around an acoustically excited micro-pillar [MS1] as a simplified model of a microswimmer tail.
[MS1] J. Ghesquiere, M. Baudoin, O. Bou Matar, S. Cleve, Microstreaming induced by the complex motion of a micro-pillar, Acoustofluidics Conference, August 2023, St Louis, USA
Surface Acoustic Waves (SAW)
In many applications, the vision can be perturbated by the presence of droplets, snow/ice or dust on optical surfaces. After working for more than ten years on the physics of droplets displacement induced by Surface Acoustic Waves (SAWs) [SW1, SW2, SW3, SW4], our team recently funded a startup commericalizing an integrated solution (Cleardrop technology) based on ultrasonic SAWs to clean optical windows. Indeed, these "nano-earthquakes" propagating at the surface of the subtrate are adsorbed by the water droplets lying on the surface provoking their displacement through two nonlinear effects called the acoustic radiation force and acoustic streaming. Note that the droplet displacement is promoted by some low frequency (in the 100Hz range) vibrations of the drop free surface, whose origin was elucidated recently in ref [SW4].
[SW1] P. Brunet, M. Baudoin, O. Bou Matar, F. Zoueshtiagh, Droplet displacement and oscillations induced by ultrasonic surface acoustic waves: a quantitative study, Phys. Rev. E, 81: 026315 (2010)
[SW2] M. Baudoin, P. Brunet, O. Bou-Matar, E. Herth, Low power sessile droplet actuation via modulated surface acoustic waves, Appl. Phys. Lett., 100: 154102 (2012)
[SW3] P. Brunet, M. Baudoin, Unstationary dynamics of drops subjected to MHz surface acoustic waves modulated at low frequency, accepted in Exp. Fluids., 63:34 (2022)
[SW4] N. Chastrette, M. Baudoin, P. Brunet, L. Royon, R. Wunenburger, Elucidating the oscillation instability of sessile drops triggered by surface acoustic waves, Phys. Rev. Fluids, 7: 124201 (2022)
Theory and analogues
Besides experimental developments, our team has worked on nonlinear acoustics theory and in particular on the acoustic radiation force [TA1, TA2] and acoutic streaming [TA3, TA4, TA5]. More recently, we have also shown theoretically, that the asymetry (due to Doppler effect) in the radiated acoustic field of a translating acoustic source, provokes a self-induced acoustic radiation force. This force can either slow down the source (as in the case of a monopolar source) [TA6] or accelerate it (in the case of a dipolar source) [TA7]. In the latter case, the source is propulsed by its own wavefield, leading to an analogy with the De Broglie double-solution pilot-wave theory, similarly to what was unveiled by Couder & Fort for the hydrodynamic quantum analogues. We are now trying to materialize these "Acoustic quantum analogues" experimentally.
[TA1] A. Riaud, M. Baudoin, J.-L. Thomas, O. Bou-Matar, Cyclones and attractive streaming generated by acoustical vortices, Phys. Rev. E, 90: 013008 (2014)
[TA2] A. Riaud, M. Baudoin, O. Bou Matar, J.-L. Thomas, P. Brunet, On the influence of viscosity and caustics on acoustic streaming in sessile droplets: an experimental and a numerical study with a cost-effective method, J. Fluid Mech., 81: 384-420 (2017)
[TA3] Z. Gong, M. Baudoin, Acoustic radiation torque on a particle in a fluid: an angular spectrum based compact expression, accepted for publication in J. Acoust. Soc. Am., 148(5): 3131-3140 (2020)
[TA4] A. Riaud, Q. Wang, Z. Gong J. Zhou and M. Baudoin, Acoustic radiation force on small spheres due to transient acoustic fields, Phys. Rev. Appl., 15: 044034 (2021)
[TA5] Z. Gong, M. Baudoin, Equivalence between angular spectrum-based and multipole expansion-based formulas of the acoustic radiation force and torque, J. Acoust. Soc. Am., 149: 3469-3482 (2021)
[TA6] A. Roux, J.P. Martishang, M. Baudoin, Self radiation force on a moving monopolar source, J. Fluid Mech., 952, A22 (2022)
[TA7] J.P. Martishang, A. Roux, M. Baudoin, Acoustic dipole surfing on its own acoustic field: toward acoustic quantum analogues, submitted (2023)