Direct optimization of femtosecond laser ablation using adaptive wavefront shaping

We introduce an approach based on using an iterative simulated annealing algorithm to drive the outcome of femtosecond laser ablation towards a specific target shape by using a two- dimensional deformable mirror. Unlike previous work combining adaptive optics and laser machining we use the machining outcome itself as the fitness parameter for the optimization procedure. Single- pulse ablation features with programmable aspect ratios and dimensions as small as 2.5 mu m are faithfully reproduced by the technique in a chromium- on- glass test sample.