Fast-beam laser lifetime measurements of the cesium 6p P-2(1/2,3/2) states

We provide a detailed description of our fast-beam laser lifetime measureme nts in atomic cesium. Selective excitation of the neutral Cs-133 6P P-2(1/2 ) and 6p P-2(3/2) states is accomplished with resonant diode laser light di rected transversely to the atomic velocity. The in-flight decay of the exci ted-state fluorescence is observed with a position-correlated single photon -counting detector. The Doppler-shifted 6p P-2(3/2) resonance, when probed with longitudinally propagating laser radiation, provides a precise means f or determination of the beam velocity, and converts the position scale to a time scale. Our lifetime results are 35.07+/-0.10 ns for the 6p P-2(1/2) s tate and 30.57+/-0.07 ns for the 6p P-2(3/2) state. These results represent a data set larger than in our previous work, and include beam divergence c orrections which have been evaluated by two different methods. We present c omparisons of our results with previous measurements and with relativistic many-body calculations of atomic transition matrix elements in this neutral alkali system. [S1050-2947(99)09711-5].