Damage and ablation of large bandgap dielectrics induced by a 46.9 nm laser beam.

We applied a 0.3 mJ, 1.7 ns, 46.9 nm soft-x-ray argon laser to ablate the surface of large bandgap dielectrics: CaF2 and LiF crystals. We studied the ablation versus the fluence of the soft-x-ray beam, varying the fluence in the range 0.05-3 J/cm2. Ablation thresholds of 0.06 and 0.1 J/cm2 and ablation depths of 14 and 20 nm were found for CaF2 and LiF, respectively. These results define new ablation conditions for these large bandgap dielectrics that can be of interest for the fine processing of these materials.