Si and Cu ablation with a 46.9-nm laser focused by a toroidal mirror

Si and Cu targets were ablated by a capillary-discharge 46.9-nm pumped laser beam, focused by a toroidal mirror at grazing incidence. The peak power density of the focal spot was ~2 × 10⁷ W/cm². Clear ablation patterns on the surfaces of Si and Cu targets were obtained, with shapes consistent with simulations.

Ce scintillator (cerium-doped YAG crystal) was used to image the variations of the laser spots. We discuss the shape and damage mechanics of the measured patterns. Melting of the target material was observed in the ablation region on Cu, but not on Si.