Plasma diagnostics by laser spectroscopy: Expensive and difficult but worth
all the trouble.

Prof. Dr. Uwe Czarnetzki, Ruhr-Universiat Bochum


In recent times, novel techniques and innovations of equipment have lead to
a substantial improvement of laser spectroscopic diagnostics on low
temperature plasmas. This applies especially to the detection of charged
species (electrons, positive and negative ions) and neutral radicals (atoms
and molecules) as well as the measurement of electric fields. Spatially and
temporally resolved measurements with high spectral resolution allow the
non-invasive determination of a whole list of important parameters, e.g.
temperature, density, velocity distribution, degree of dissociation,
diffusion and reaction rates, sticking coefficients, voltages, currents
etc.. However, the techniques available are mostly limited to a certain
dynamic range and their applicability is determined strongly by the
experimental conditions. Therefore, one usually has to make a choice out of
a spectrum of alternatives and sometime a novel development is required. The
talk intends to give an overview on recent developments by introducing
selected examples.