Saturation spectroscopy of ion metastables in plasmas

An absorption coefficient and hence the population density of metastable states 3d 4 F, 3d 2 P, 3d' 2 G were measured by a single-frequency dye laser in gas-discharge plasma. It has been shown that population distribution between levels of multiplet 3d 4 F J can be described by Boltzmann's low with temperature close to that for heavy particles. Relaxation constants measured from absorption saturation curves have close values for different metastables and are approximately equal to (Gamma) n approximately equals (2 divided by 6) X 10 7 s -1 . High value of relaxation constants means high excitation rates of metastable levels. Linear dependence of (Gamma) n on electron density was shown for 3d 4 F 7/2 level. It has been demonstrated that electrons are of great importance in the deactivation process. The measured parameters of levels are used for evaluation of output characteristics of three-level Raman laser with metastable start and final levels.