Quantification of laser-induced damage growth using fractal analysis.

Lateral and longitudinal laser damage growth under subsequent irradiations at 351 nm in the nanosecond range from micrometric to millimetric scales is presented herein. Atypical behavior has been observed, showing the growth in the longitudinal direction, whereas the lateral growth does not evolve. We propose the use of fractal analysis to describe the evolution of the bulk damage morphology. The results indicate first a dependence between the damage fractal dimension and the laser parameters, such as the fluence and the pulse duration. Next, it seems from observations that the damage morphology modifications drive the growth rate changes.