Spectroscopic studies of magnesium plasma produced by fundamental and second harmonics of Nd:YAG laser

Abstract

In the present experimental work, laser induced magnesium plasma has been characterized using plasma parameters. The plasma has been generated by the fundamental (1064 nm) and second harmonics (532 nm) of Nd:YAG laser. The plasma parameters such as electron temperature and electron number density have been extracted using Boltzmann plot method and Stark broadened line profile, respectively. The laser irradiance dependence and spatial behavior of electron temperature and number density in laser induced magnesium plasma have been studied. The electron temperature as a function of laser irradiance (0.5 to 6.5 GW/cm2) ranges from (9.16–10.37) × 103 K and (8.5–10.1)× 103 K, and electron number density from (0.99–1.08) × 1016 cm−3 and (1.04–1.22) × 1016cm−3 for 1064 and 532 nm, respectively. These parameters exhibit fast increase at low laser irradiance and slow increase at high irradiance. The spatial distribution of electron temperature and electron number density shows same decreasing trend up to 2.25 mm from the target surface. The electron temperature and number density decrease from (9.5–8.6) × 103 K, (1.27–1.15) × 1016cm−3 and (10.56–8.85)× 103 K, (1.08–0.99) × 1016 cm−3 for 532 nm and 1064 nm laser ablation wavelengths, respectively.