Laser fluorescence and absorption spectroscopy of laser ablation plasmas

The application of optical emission spectroscopy for ablation plasmas diagnostics has already a long tradition. Nevertheless a lot of papers the complete understanding of the fundamental properties of the plasmas produced during ablation is lacking. The great variety and complexity of physical processes involved in laser radiation interaction with a target require more sensitive laser spectral methods. The most efficient are laser-induced fluorescence (LIF) and absorption intracavity laser spectroscopy (ICLS). The well known LIF based on the selective excitation of plasmas species is an ultrahigh sensitive method with wide diagnostic possibilities. It has been for the first time used for high temperature plasmas diagnostics by the authors of this paper. Rarely used the ICLS is based on the variation of a frequency-dependent laser losses when placing inside a cavity a substance with absorption lines lying within the active medium gain contour. As a result, radiation weakening on the selective losses frequencies is observed. (author) 2 refs