Shock wave and emission with sheet-like structure induced by Nd-YAG laser ablation at reduced pressure

A Nd-YAG laser (8 ns, 79 mJ) was focused in air at 5 Torr on a zinc target in front of which a thin wire (0.32 mm phi) was placed as an obstacle near the laser focusing point (2 min from the target and 0,75 turn from the axis of laser beam). As a result, a sheet-like plasma is produced with two branches. showing a V-shape emission structure when observed from the side. When two wires were symmetrically placed against the laser beam, a sheet-like plasma with three branches appeared with the strongest emission in the middle. Simultaneous detection was made on the middle sheet-like plasma to prove the coincidence of the Zn I 481.0 nm emission front due to propelling atoms and the density jump due to the shock wave. It was shown that the total emission intensity is almost independent of the structure of the secondary plasma.