Wavelength Shift Investigation of Optical Emission from Nanosecond Pulsed Laser Ablated Metal Al

The wavelength shift of optical emission from pulsed laser ablation of metal Al in 1atm air has been investigated by using the time-resolved optical emission spectroscopy (OES). The wavelength shift of OES has a second order exponential decay with time and was also found to be significantly influenced by the laser ablated pulse energy. By taking account of the shielding effect of free electrons inside of the plasma plume, the relation between the electron density and wavelength shift has been discussed.