Influence of Atmosphere and Irradiation Wavelength on Copper Plasma Emission Induced by Excimer and Q-Switched Nd:YAG Laser Ablation

Abstract

Laser-induced copper plasma emission was investigated by time-integrated spatially resolved spectrometry. The comparative work on the plasma emission characteristics—specifically, self-absorption, line broadening, emission intensity, and metal ion formation—was carried out by the use of two different laser systems (XeCl excimer: = 308 nm; Nd:YAG: = 1064 and 532 nm). The characteristics of plasma emission produced by different wavelength radiation on copper atomic and ion lines under various atmospheric gases (argon, neon, and helium) and pressures (760–10 Torr) are presented. The differences in self-absorption and line broadening phenomena in the plasma location were explained by shock wave-driven excitation mechanism for atoms in the outer region in the plasma. The excitation temperatures of the plasma induced by 308- or 532-nm irradiation were also much higher that those induced by 1064-nm irradiation.