The effect of temporal pulse shaping in ultrafast laser ablation of dielectrics

Summary from only given. Femtosecond laser ablation of dielectrics, especially of brittle materials, often results in specific collateral damage in the form of fracture and exfoliation, as a consequence of the mechanical stress induced in the material. Fast electronic relaxation in solids with strong electron-phonon coupling establishes a guideline for using temporally-shaped pulses to exploit dynamical processes and optimize structuring with respect to the reduction of the residual damage. First effects of a modulated excitation were extracted by studying laser-induced optical damage with temporally tailored pulses. Two extreme cases were considered; /spl alpha/-SiO/sub 2/ with 100 fs electron trapping in self-induced deformations and Al/sub 2/O/sub 3/ where electrons remain quasi-free for tens of ps.