Time evolution of the infrared laser ablation plasma plume of SiO

摘要

The spatio-temporal evolution of the silicon monoxide SiO plasma produced by a high-power CO_2 pulsed laser has been investigated using optical emission spectroscopy (OES) and imaging methods. The formed plasma was found to be strongly ionized, yielding Si~+, O~+, Si~(2+), O~(2+) and Si~(3+) species, rich in neutral silicon and oxygen atoms, and very weak molecular bands of SiO time-integrated and time-resolved two-dimensional OES plasma profiles were recorded as a function of emitted wavelength and distance from the target. The temporal behavior of specific emission lines of Si, Si~+, O~+, Si~(2+) and O~(2+) was characterized. The results show a faster decay of O~(2+) and Si~(2+) than that of O~+, Si~+ and Si. The Stark broadening of isolated single-ionized silicon emission lines was employed for deducing the electron density during the plasma expansion. The relative intensities of two Si~(2+) lines were used to calculate the time evolution of the plasma temperature.