Photon statistics in resonance fluorescence: Results from an atomic-beam deflection experiment

Photon-number statistics in resonance fluorescence is studied through the deflection of a beam of neon atoms in the metastable ${}_{}{}^3{}_{}{}^{}$ ${\mathit{P}}_2$ state by radiation pressure. An analysis of the deflection profile leads to experimental values for the Mandel Q parameter as a function of laser intensity and detuning for different laser polarizations. The results confirm the predicted predominantly sub-Poissonian statistics. Good agreement is demonstrated with the results of a Monte Carlo calculation based on a pure-state analysis of resonance fluorescence.