We report a measurement of the lifetime of the cesium 7s 2S1/2 state using time-correlated single-photon counting spectroscopy in a vapor cell. We excite the atoms using a Doppler-free two-photon transition from the 6s 2S1/2 ground state, and detect the 1.47-μm photons from the spontaneous decay of the 7s 2S1/2 to the 6p 2P3/2 state. We use a gated single-photon detector in an asynchronous mode, allowing us to capture the fluorescence profile for a window much larger than the detector gate length. Analysis of the exponential decay of the photon count yields a 7s 2S1/2 lifetime of 48.28 ± 0.07 ns, an uncertainty of 0.14%. These measurements provide sensitive tests of theoretical models of the Cs atom, which play a central role in parity violation measurements.


This is the publisher's version. Version of record:

Toh et al. (2018). “Measurement of the lifetime of the 7s2S1/2 state in atomic cesium using asynchronous gated detection,” Physical Review A, 97(052507). doi: https://doi.org/10.1103/PhysRevA.97.052507


electronic structure of atoms and molecules, electronic transitions

Date of this Version




To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.