  We study laser cooling of atomic gases by collisional redistribution of
fluorescence. In a high pressure buffer gas regime, frequent collisions perturb
the energy levels of alkali atoms, which allows for the absorption of a far red
detuned irradiated laser beam. Subsequent spontaneous decay occurs close to the
unperturbed resonance frequency, leading to a cooling of the dense gas mixture
by redistribution of fluorescence. Thermal deflection spectroscopy indicates
large relative temperature changes down to and even below room temperature
starting from an initial cell temperature near 700 K. We are currently
performing a detailed analysis of the temperature distribution in the cell. As
we expect this cooling technique to work also for molecular-noble gas mixtures,
we also present initial spectroscopic experiments on alkali-dimers in a dense
buffer gas surrounding.
