Absorption spectroscopic measurement of atomic density in laser-induced vapor plume

Abstract

Laser absorption spectroscopy employing a tunable continuous wave dye laser has been used to measure the density of atomic niobium vapor in a laser ablation plume near the target. Population densities for one atomic level were measured to be ~ 1015 cm-3 near the center of the plume. Electron excitation temperatures within the plume were measured to be in the range 3500–4500 K. Use of the measured temperatures to sum over population of all atomic levels and integration of the resulting density distribution over the plume volume results in a measurement of ~ 1015 niobium atoms ablated per pulse. This is in good agreement with estimates based on change in mass of the target over the course of an experimental run.Laser absorption spectroscopy employing a tunable continuous wave dye laser has been used to measure the density of atomic niobium vapor in a laser ablation plume near the target. Population densities for one atomic level were measured to be ~ 1015 cm-3 near the center of the plume. Electron excitation temperatures within the plume were measured to be in the range 3500–4500 K. Use of the measured temperatures to sum over population of all atomic levels and integration of the resulting density distribution over the plume volume results in a measurement of ~ 1015 niobium atoms ablated per pulse. This is in good agreement with estimates based on change in mass of the target over the course of an experimental run.