Characterization of laser induced tantalum plasma by spatio-temporal resolved optical emission spectroscopy

The spatial and temporal behavior of the tantalum plasma produced in air by third harmonic Nd:YAG laser (0.6 GW cm⁻²) has been studied using optical emission spectroscopy. Excitation temperature and electron density have been estimated from the analysis of spectral data as well as their spatio-temporal evolutions. As the delay time increases from 400 to 2000 ns, the excitation temperature has found to decrease from 10,000 K to 7900 K. The value of N_e decreases continuously from 4 × 10¹⁸ near the zero position to 5 × 10¹⁷ in a linear approach along with the propagation axe of the plasma plume. Laser-supported consumption wave regime has been proposed to explain the propagation of the plasma.