Measurement of the lifetime of the 7S1/2 state in atomic cesium using asynchronous gated detection*

Our group is making progress towards new parity violation measurements in cesium. Atomic lifetime measurements provide sensitive tests of theoretical models of the cesium atom, which play a central role in parity violation measurements. We report a measurement of the lifetime of the cesium $7s^2~S_{1/2}$ state using time-correlated single photon counting spectroscopy. We excite the atoms using a Doppler-free two-photon transition from the ground state, and detect the $1.47~\mu m$ photons from spontaneous decay. We introduce an asynchronous detection technique using gated single photon detectors, allowing us to capture the fluorescence profile for a time window much larger than the detector gate length.