Depth profile of a time-reversal focus in an elastic solid

International audience; The out-of-plane velocity component is focused on the flat surface of an isotropic solid sample using theprinciple of time reversal. This experiment is often reproduced in the context of nondestructive testingfor imaging features near the surface of the sample. However, it is not clear how deep the focus extendsinto the bulk of the sample and what its profile is. In this paper, this question is answered using bothnumerical simulations and experimental data. The profiles of the foci are expressed in terms of the wavelengthsof the dominant waves, based on the interpretation of the Lamb’s problem and the use of the diffractionlimit.