Ion and neutral emission from pulsed laser irradiation of metals

An Nd:YAG pulsed laser at 1064 nm wavelength with 9 ns pulse width and a ma ximum pulse energy of 900 mJ is focused on different metallic targets (Al, Ti, Ni, Cu, Nb, Sn, Ta, W, An and Pb) placed in vacuum. The interaction pro duces a high etching for a pulse energy higher than a threshold value typic al of each metal. Near the threshold a strong neutral emission takes place; at high pulse energy a stronger ionic emission occurs. The experimental th resholds of the ion emission are very similar to the threshold of the neutr al emission. The atomic neutral emission is monitored by a mass quadrupole spectrometer and by the vapor thin film deposition technique. The ionic emi ssion is detected through ion collectors (IC) using Faraday cups and time-o f-flight measurements. The energy thresholds, the emission yields, the angu lar distribution, the fractional ionization, the kinetics and characteristi cs of the plasma production and the ion charge state are presented and disc ussed. (C) 2001 Published by Elsevier Science B.V.