Collective strong coupling of cold potassium atoms in a ring cavity

TL;DR

This paper demonstrates collective strong coupling between cold potassium atoms and a ring cavity, showing clear spectral signatures of quantum electrodynamics phenomena in a novel atomic system.

Contribution

It reports the first observation of strong coupling with potassium atoms in a ring cavity, expanding experimental capabilities in cavity QED.

Findings

Observation of spectral splitting indicating strong coupling

Demonstration of normal mode avoided crossing

Implementation of cold potassium atom trapping in cavity

Abstract

We present experiments on ensemble cavity quantum electrodynamics with cold potassium atoms in a high-finesse ring cavity. Potassium-39 atoms are cooled in a two-dimensional magneto-optical trap and transferred to a three-dimensional trap which intersects the cavity mode. The apparatus is described in detail and the first observations of strong coupling with potassium atoms are presented. Collective strong coupling of atoms and light is demonstrated via the splitting of the cavity transmission spectrum and the avoided crossing of the normal modes.