Effect of ambient gas pressure and nature on the temporal evolution of aluminum laser-induced plasmas

Time-resolved analysis of emission spectra, electron densities and excitation temperatures of Aluminum laser induced plasmas produced in argon, nitrogen and helium at different pressures have been studied experimentally. The plasma emission intensity is found to be strongly affected by the plume confinement and differs with the nature of the ambient gas and its pressure. Our observations show that both electron density and excitation temperature increase with the ambient gas pressure. In addition, Argon was found to produce the highest plasma density and temperature and Helium the lowest, while Nitrogen yields intermediate values.