Surface Ablation of Dielectrics with sub-10 fs to 300 fs Laser Pulses: Crater Depth and Diameter, and Efficiency as a Function of Laser Intensity

Surface ablation of a dielectric material (fused silica) is studied as a function of pulse duration (< 10 fs -300 fs) and applied fluence (F th < F < 10 F th ) using single femtosecond pulse. We show that the axial selectivity (crater depth) depends on the applied intensity while the transverse selectivity (crater diameter) only depends on the applied fluence. The ablation efficiency, expressed in m 3 /J, is shown to be inversely proportional to the pulse duration and saturates with respect to the applied fluence earlier at short pulse durations ( 30 fs). The deduced optimal fluence F opt, corresponding to the highest ablation efficiency for each pulse width, defines two regimes of laser application, characterized either by high selectivity (F < F opt ) or high control (F > F opt ) of ablation characteristics.