Dephasing of ultracold cesium 80D5/2-Rydberg electromagnetically induced transparency

We study Rydberg electromagnetically induced transparency (EIT) of a cascade three-level atom involving 80D(5/2) state in a strong interaction regime employing a cesium ultracold cloud. In our experiment, a strong coupling laser couples 6P(3/2) to 80D(5/2) transition, while a weak probe, driving 6S(1/2) to 6P(3/2) transition, probes the coupling induced EIT signal. At the two-photon resonance, we observe that the EIT transmission decreases slowly with time, which is a signature of interaction induced metastability. The dephasing rate ?(OD) is extracted with optical depth OD = ?(t)(OD). We find that the optical depth linearly increases with time at onset for a fixed probe incident photon number R-in before saturation. The dephasing rate shows a nonlinear dependence on R-in. The dephasing mechanism is mainly attributed to the strong dipole-dipole interactions, which leads to state transfer from nD(5/2) to other Rydberg states. We demonstrate that the typical transfer time t(0(80D)) obtained by the state selective field ionization technique is comparable with the decay time of EIT transmission t(0(EIT)). The presented experiment provides a useful tool for investigating the strong nonlinear optical effects and metastable state in Rydberg many-body systems.

Automated summary

In this experiment, we study the Rydberg electromagnetically induced transparency (EIT) of a cascade three-level atom involving the 80D(5/2) state in a strong interaction regime using a cesium ultracold cloud. We observe a slow decrease in EIT transmission over time at two-photon resonance, indicating interaction-induced metastability. The dephasing rate is found to have a nonlinear dependence on the incident photon number. The main dephasing mechanism is attributed to strong dipole-dipole interactions and state transfer to other Rydberg states.