Peculiar long-term fluorescence of Rb atoms in coated vapor cell with internal atomic source

TL;DR

This study observes an unusually long fluorescence decay in Rb atoms within coated vapor cells, revealing non-exponential decay behavior linked to high-quality coatings and ground-state population dynamics.

Contribution

It demonstrates that long-term fluorescence decay in Rb vapor cells is due to ground-state population pumping, supported by numerical simulations, highlighting the role of cell coating quality.

Findings

Decay time exceeds several milliseconds, much longer than typical.

Decay is non-exponential and depends on coating quality.

Simulation confirms ground-state population pumping as the mechanism.

Abstract

We report on an experiment in which the fluorescence decay time of 5P levels of Rb atoms in a coated vapor cell exceeds several of milliseconds, many orders of magnitude longer than normal decay time of excited of rubidium atoms. We found that this peculiarly long - term decay is not exponential and can only be observed in a high quality coated cell with a long lifetime of optical pumped atoms on atomic ground-state sublevels. A numerical simulation based on a complete density matrix is presented. It supports the population pumping process through the ground-state sublevels of Rb atoms as the most plausible mechanism for the observed phenomenon and it consistently demonstrates all the relevant features of the experiment. The investigation can be used, for example, to explore the quality of a various anti-relaxation coatings used for the resonant cells.