DIAGNOSTICS OF COPPER PLASMA PRODUCED BY THE FUNDAMENTAL, SECOND AND THIRD HARMONICS OF A Nd:YAG LASER

Abstract

We report measurements of the copper plasma parameters generated by the fundamental, second and third harmonics of a Nd:YAG laser. The 3 d94 s 5 s2D3/2→3 d94 s 4 p2F5/2at 464.25 nm, 4p2P3/2→3 d94 s2D5/2at 510.55 nm, 4d2D3/2→4 p2P1/2at 515.32 nm 4d2D5/2→4 p2P3/2at 521.82 nm and 4p2P3/2→3 d94 s2D3/2at 570.02 nm transitions have been used to estimate the electron temperature through the Boltzmann plot method. The number density has been estimated from the Stark broadened profiles of the spectral lines. The spatial behaviour of the electron temperature and number density has been examined at different ambient air pressures and with laser irradiance. The temperature and number density are found to be in the range from 14700 to 13600 K and 2.1×1016to 1.78×1016cm-3for the 1064 nm laser, from 14200 to 12800 K and 2.2×1016to 1.8×1016cm-3for the 532 nm laser and from 14100 to 12500 K and 2.4×1016to 1.9×1016cm-3for the 355 nm laser.