Measurement of electron density and temperature of a laser-induced zinc plasma

We report spectroscopic studies of the zinc plasma produced in air by the three harmonics of a Q-switched pulsed Nd : YAG laser at 1064, 532 and 355 nm. The electron temperature has been determined from the intensity ratio of the transitions (4s4d 3D3 → 4s4p 3P2) at 334.5 nm and (4s5s 3S1 → 4s4p 3P2) at 481.0 nm of neutral zinc, whereas the electron number density has been evaluated from the Stark broadening of the (4s4d 3D3 → 4s4p 3P2) transition at 334.5 nm. It is observed that both these parameters decrease as the distance from the target surface increases and it increases with an increase in the laser irradiance. The power law is fitted to the experimental data.