Spallation generated by femtosecond laser driven shocks in thin metallic targets
Résumé
Spallation induced by a laser driven shock has been studied for two decades on time scales of nanosecond order. The evolution of laser technologies now opens access to sources whose pulse duration is under the picosecond, corresponding to characteristic times of numerous microscopic phenomena. In this ultra-short irradiation regime, spallation experiments have been performed with time-resolved measurements of the free surface. These measurements, complemented with post-test observations, have been compared with numerical simulations to check the consistency of modelling of the laser-matter interaction, shock propagation and to the study of dynamic damage at this ultra-short time scale, inducing strong tensile stress states at very high strain rates.