Progress toward precise determination of atomic lifetimes using photon echoes

We review the progress of a photon echo experiment for sensitive measurements of atomic lifetimes. Using short-pulse excitation of atomic rubidium vapor, we have recently reported the most statistically precise measurement of (26.11 ± 0.03) ns for the 5² P_3/2 lifetime*. The experiment relies on heterodyne detection and exploits the signal-to-noise ratio of the coherent release of energy along the direction of excitation, which is an exponential decay as a function of pulse separation T, as well as large repetition rates that are feasible in a heated vapor cell. We describe a background subtraction technique for simultaneously recording signal and background pulses at repetition rates of 1MHz. We expect this technique to overcome technical limitations and allow the exploration of systematic effects.

* H. C. Beica et al., Phys. Rev A 101, 033408 (2020)