Generation of shear waves by laser in soft media in the ablative and thermoelastic regimes

This article describes the generation of elastic shearwaves in a soft medium using alaser beam. Our experiments show two different regimes depending on laser energy. Physical modeling of the underlying phenomena reveals a thermoelastic regime caused by a local dilatation resulting from temperature increase and an ablative regime caused by a partialvaporization of the medium by the laser. The computed theoretical displacements are close to the experimental measurements. A numerical study based on the physical modeling gives propagation patterns comparable to those generated experimentally. These results provide a physical basis for the feasibility of a shearwaveelastography technique (a technique that measures a soft solid stiffness from shearwave propagation) by using alaser beam.

Source: Applied Physics Letters - November 28, 2016 Category: Physics Authors: Pol Grasland-Mongrain, Yuankang Lu, Fr édéric Lesage, Stefan Catheline and Guy Cloutier Source Type: research