Effect of anisotropy on atomic fluorescence: Influence on the detection of a hyperfine transition in a cesium beam

Abstract
The problem of the fluorescence anisotropy resulting from alignment in the excited state is investigated in the case of a cesium beam illuminated by a broadband laser diode tuned to the cesium D2 line. Its effect on the collection efficiency is derived when photon fluorescence collection is performed inside a small solid angle about the quantization axis. Excitation schemes leading to a noticeable increase of the fluorescence yield are pointed out and experimental results agree quite well with the predictions.