Tóm tắt:

We observed the formation of damage induced by focusing a nanosecond laser beam inside a glass block using the shadowgraph imaging technique. The damage growth was observed during some first dozens of nanoseconds of the process. The result shows that the damage growth is divided into two periods. During the laser pulse, the damage grows quickly, following the formation of laser induced plasma. When the laser is switched off, the damage grows at a much slower rate. We propose that the growth of damage during the second period is due to the propagation of the shear wave inside the material.