High-speed diagnostics of laser deformation development in transparent dielectrics

The paper aims to investigate the dynamics of the crater growth and of changes in the density of an inelastically deformed material, as well as the generation of acoustic waves on the surface of a transparent insulator when it interacts with a millisecond light pulse that has a complex temporal profile. Investigation shows that the effective growth of the crater formed as a result of the interaction of a laser pulse of duration at least /spl sim/1 ms with the surface of the transparent insulator did not last more than 100 /spl mu/s. The crater growth dynamics is governed primarily by the evaporation mechanism: the individual spikes of a laser pulse interacting with the target did not influence the growth process. On the other hand, each spike of this kind created a train of acoustic vibrations which can be described satisfactorily by a model of a loaded region emitting a wave into an elastic medium.