Measurements of single-state and state-ensemble lifetimes of high-lying Rb Rydberg levels

Abstract

We demonstrate a hybrid method based on field ionization and state-selective de-excitation capable of measuring the lifetimes of high-lying Rydberg states. For nS Rydberg states of Rb atoms with principal quantum number 60 ≤ n ≤ 88, we measure both the individual target state lifetimes and those of the ensemble of Rydberg states populated via black-body radiation-induced transitions. We find good overall agreement with numerical calculations of the expected lifetimes in both cases. However, for the target state lifetimes, we find a local deviation towards shorter lifetimes for states around n = 72, which we interpret as a signature of a modified black-body spectrum in the finite volume in which our experiments take place.

Measurements of blackbody radiation-induced transition rates between high-lying S, P and D Rydberg levels

“…Our measurements of BBR-induced Rydberg-Rydberg transition rates are based on a combination of stateselective depumping [2] and field ionization, as described in detail in [1]. A schematic of the protocol is reported in Fig.…”

“…1(b)) and monitoring the resulting Stark shift of an nS Rydberg state (typically between n = 90 and n = 105) as well as the separation of that state from the adjacent n − 3 manifold (for details see the Appendix). In this way, we are able to compensate the stray fields to within 15 mV/cm, allowing us to work with principal quantum numbers up to 110, for which the Inglis-Teller limit is 33 mV/cm (when the stray fields approach or exceed the Inglis-Teller limit, the measured single-state lifetimes drop sharply and no longer reflect the actual lifetimes of the target states [1]).…”

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We report experimental measurements of the rates of blackbody radiation-induced transitions between high-lying (n > 60) S, P and D Rydberg levels of rubidium atoms in a magneto-optical trap using a hybrid field ionization and state-selective depumping technique [1,2]. Our results reveal significant deviations of the measured transition rates from theory for well-defined ranges of the principal quantum number.

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“…Such measurements require a method that allows one to distinguish between a target nL state and nearby n ′ L ′ states, which can be as close as a few GHz in frequency units. In this paper, we use a method we recently presented in [1] which combines field ionization with state-selective depumping [2] to measure the lifetimes of single Rydberg states and of state-ensembles (i.e., all the Rydberg levels that are populated by BBR), from which transition rates can be calculated. Furthermore, this method allow us also to observe the evolution of the population of the support states, i.e., all the populated Rydberg states except the target one.…”

Redistribution of the Rydberg State Population Induced by Continuous-Spectrum Radiation

“…Thus, a strong perturbation of the atomic spectrum is not necessary to produce multistep transitions, which can instead be induced by less intense radiation. In general, the study of continuousspectrum radiation effect on Rydberg states began more than four decades ago with the pioneering work by Gallagher and Cooke [11] and continued in many experimental and theoretical works concerning interaction of the Rydberg states with the blackbody radiation, for example [12][13][14][15]. However, long multistep transitions in this case have been much less studied than in the monochromatic radiation case.…”