Laser cooling of atoms by collisional redistribution of fluorescence

This study experimentally demonstrates laser cooling of rubidium atoms subjected to 500 bar of buffer gas pressure based on the collisional redistribution of fluorescence. The frequent collisions in the ultradense gas transiently shift a far red detuned laser beam into resonance, while spontaneous decay occurs close to the unperturbed atomic resonance frequency. In a proof of principle experiment, a relative cooling by 33 K is observed.