Abstract
Single atoms are detected and their motion measured for the first time to our knowledge by the fluorescence photonburst method in the presence of large quantities of buffer gas. A single-clipped digital correlator records the photon burst in real time and displays the atom's transit time across the laser beam. A comparison is made of the special requirements for single-atom detection in vacuum and in a buffer gas. Finally, the probability distribution of the bursts from many atoms is measured. It further proves that the bursts observed on resonance are due to single atoms and pot simply to noise fluctuations. © 1980, Optical Society of America.