# Transient fluorescence with a single trapped ion

## TL;DR

This paper introduces a method to measure transient fluorescence dynamics of a single trapped ion, revealing detailed atomic properties and system parameters through time-resolved photon detection.

## Contribution

The work demonstrates a novel approach to record and analyze transient fluorescence in single ions, linking experimental data with quantum system simulations.

## Key findings

- Measured optical pumping times between ion states
- Achieved good agreement with quantum simulations
- Extracted atomic and experimental parameters from fluorescence curves

## Abstract

In this paper we present a method to measure transient fluorescent dynamics with single trapped ions in a Paul trap. We use $^{40}$Ca$^+$ ions which exhibit a $\Lambda$-type three-level system and measure the characteristic optical pumping times between the ground $S_{1/2}$ and the meta-stable $D_{3/2}$ levels. We prepare one of these states, then pump it to the opposite via the excited $P_{1/2}$ state. By measuring the scattered photons of the ion, we retrieve transient curves of the atomic fluorescence. These curves provide fundamental information about the atomic system, such as branching fractions and excited-state lifetimes, as well as experimental parameters like the efficiency of the detection system and the saturation parameter of one of the transitions. Finally, we study the time dependent fluorescence as a function of optical power and detuning of the lasers and find a very good agreement with simulating the dynamics via a three-level open quantum system through a set of optical Bloch equations. Being able to record time dependent fluorescence is of particular interest as it contains information about the temperature, cooling and heating dynamics of the ion.