Photon statistics of light resonantly scattered from a three-level atom
R. M. Evans
Abstract
A laser spectroscopy system and the equipment needed for resonance-fluorescence studies with the photon-burst method in an extended interaction region were developed. To accommodate the long, variable transit times of thermal atoms across this extended region a resettable coincidence counter was used;The photon statistics of light scattered from the three-level 5535 A transition in barium were investigated. These statistics agreed well with theory developed in conjunction with this work. An atomic branching ratio of 375 (+OR-) 30 was obtained from the photon number distributions, establishing a new method for determining this quantity. The affect of radiation pressure upon the photon-burst lineshapes was observed. Because of the large number of photons scattered high sensitivity was obtained, allowing measurements with fluxes of less than one atom/sec. The results of this work are important for the study of the hyperfine structure of atoms with short-lived nuclei and in searches for long-lived but exotic nuclei.