Measurement of the lifetime of the $7s^2S_{1/2} $ state in atomic cesium using asynchronous gated detection

TL;DR

This paper measures the lifetime of the cesium 7s state using advanced photon detection techniques, providing precise experimental data to test theoretical models relevant for fundamental physics tests.

Contribution

It introduces a novel asynchronous gated detection method for accurate lifetime measurement of atomic states in vapor cells.

Findings

Measured the cesium 7s state lifetime as 48.28±0.07 ns

Achieved an uncertainty of 0.14% in the lifetime measurement

Demonstrated the effectiveness of asynchronous gated detection for atomic spectroscopy

Abstract

We report a measurement of the lifetime of the cesium $7s\,^2S_{1/2}$ 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 $6s\,^2S_{1/2}$ ground state, and detect the 1.47$\mu$m photons from the spontaneous decay of the $7s\,^2S_{1/2}$ to the $6p\,^2P_{3/2}$ 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 $7s\,^2S_{1/2}$ lifetime of 48.28$\pm$0.07ns, 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.