Lifetime and hyperfine splitting measurements on the 7s and 6p levels in rubidium

Abstract

We present lifetime measurements of the 7S1/2 level and the 6p manifold of rubidium. We use a time-correlated single-photon counting technique on a sample of 85Rb atoms confined and cooled in a magneto-optic trap. The upper state of the 5P1/2 repumping transition serves as the resonant intermediate level for two-photon excitation of the 7s level. A probe laser provides the second step of the excitation, and we detect the decay of atomic fluorescence to the 5P3/2 level at 741 nm. The decay process feeds the 6p manifold that decays to the 5s ground state emitting UV photons. We measure lifetimes of 88.07±0.40 and 120.7±1.2 ns for the 7S1/2 level and 6p manifold, respectively; the hyperfine splitting of the 7S1/2 level is 282.6±1.6 MHz. The agreement with theoretical calculations confirms the understanding of the wave functions involved and provides confidence on the possibility of extracting weak interaction constants from a parity nonconservation measurement.