Shear-wave focusing with a laser-ultrasound phased-array

摘要

Pulsed laser arrays have been used to improve the beam parametersnof laser generated ultrasound. The focusing and steering ofnshear-acoustic-wave beams generated by an array of thermoelastic sourcesnhas been investigated. A modeling of the impulse diffraction response ofna single line source was derived from the point source model (SurfacenCenter Of Expansion) of the thermoelastic source. The acoustic fieldnlaunched by an array of point- or line-sources has been computed.nExperimentally, the impulse response of a line source has been measurednby using a heterodyne interferometer. It was shown with a 16-beam YAGnlaser, that shear-acoustic-wave beams can be focused and steered insidena duraluminum sample with a great efficiency