# Cavity-induced anti-correlated photon emission rates of a single ion

## TL;DR

This paper demonstrates how a high finesse optical cavity can modify emission rates of a single ion, enhancing IR emission via the Purcell effect while suppressing UV fluorescence, revealing new control over ion-photon interactions.

## Contribution

It reports the first observation of cavity-induced anti-correlated emission rates in a single ion, with the largest IR ion-cavity coupling measured to date.

## Key findings

- 66% suppression of UV fluorescence due to cavity effects
- Achieved the highest reported IR ion-cavity coupling of 2π·5.3 MHz
- Demonstrated simultaneous enhancement and suppression of emission channels

## Abstract

We report on the alteration of photon emission properties of a single trapped ion coupled to a high finesse optical fiber cavity. We show that the vacuum field of the cavity can simultaneously affect the emissions in both the infrared (IR) and ultraviolet (UV) branches of the $\Lambda-$type level system of $^{40}\mathrm{Ca}^+$ despite the cavity coupling only to the IR transition. The cavity induces strong emission in the IR transition through the Purcell effect resulting in a simultaneous suppression of the UV fluorescence. The measured suppression of this fluorescence is as large as 66% compared with the case without the cavity. Through analysis of the measurement results, we have obtained an ion-cavity coupling of $\bar{g}_0 = 2\pi\cdot (5.3 \pm 0.1)$ MHz, the largest ever reported so far for a single ion in the IR domain.