Diagnostics of a Potassium Plasma Produced by Visible and IR Nanosecond Laser Ablation

We present spectroscopic emission studies of a laser-produced potassium plasma generated by the fundamental mode (1064 nm) and the second harmonic (532 nm) of a Q-switched pulsed Nd:YAG laser. The spectra predominantly reveal the spectral lines of neutral potassium. We use experimentally observed line profiles of neutral potassium to determine the excitation temperature using Boltzmann plots, and the Stark-broadened line profiles to determine the electron-number density. We also study variations in the excitation temperature and electron-number density as functions of the laser irradiance.