Abstract
We report a measurement of the 5๐3โ2 excited-state lifetime using two-pulse photon echoes in Rb vapor. The measurement is precise to โผ1% and agrees with the best measurement of atomic lifetime in Rb. The results suggest that a measurement precise to โผ0.25% is possible through additional data acquisition and study of systematic effects. The experiment relies on short optical pulses generated from a cw laser using acousto-optic modulators. The excitation pulses are on resonance with the ๐น=3โ๐นโฒ=4 transition in Rb85 or the ๐น=2โ๐นโฒ=3 transition in Rb87. The resulting photon echo signal is detected using a heterodyne detection technique. The excited-state lifetime is determined by measuring the exponential decay of the echo intensity as a function of the time between the excitation pulses. We also present a study of the echo intensity as a function of excitation pulse area and compare the results to simulations based on optical Bloch equations. The simulations include the effects of spontaneous emission as well as spatial and temporal variations of the intensities of excitation pulses.