# Coherent population pumping in a bright state

## TL;DR

This paper reports the experimental observation of coherent population pumping resonances in a bright state in rubidium vapor, analyzing the effects of pump power and buffer gas on the resonance linewidth, supported by theoretical modeling.

## Contribution

It presents the first experimental demonstration of CBS in a bright state using $^{87}$Rb and analyzes the influence of pump power and buffer gas on the resonance.

## Key findings

- CBS resonances observed in $^{87}$Rb vapor at room temperature.
- Linewidth of CBS affected by pump power, explained via scattering rate.
- Theoretical density-matrix model supports experimental results.

## Abstract

We demonstrate resonances due to coherent population pumping in a bright state (CBS), using magnetic sublevels of the closed $ F_g = 2 \rightarrow F_e = 3 $ transition in $^{87}$Rb. The experiments are performed at room temperature vapor in two kinds of cells---one that is pure and the second that contains a buffer gas of Ne at 20 torr. We also present the effect of pump power variation on the CBS linewidth, and explain the behavior by using a power-dependent scattering rate. The experimentally observed CBS resonances are supported by a density-matrix analysis of the system.