Production of rovibronic ground state RbCs molecules via two-photon cascade decay

TL;DR

This paper demonstrates a method to produce ultracold RbCs molecules in their rovibronic ground state through a two-photon cascade decay process following short-range photoassociation, enabling easier manipulation of these molecules.

Contribution

It introduces a new, simplified scheme for creating rovibronic ground state RbCs molecules via a two-step cascade decay, with detailed spectroscopic analysis.

Findings

Up to 33% branching into J=0 rotational level

Confirmation of cascade decay as primary decay route

Potential for easier access to ultracold heteronuclear molecules

Abstract

We report the production of ultracold RbCs molecules in the rovibronic ground state, i.e., $X^1\Sigma^+ (v=0, J=0)$, by short-range photoassociation to the $2^3\Pi_{0}$ state followed by spontaneous emission. We use narrowband depletion spectroscopy to probe the distribution of rotational levels formed in the $X ^1\Sigma^+(v=0)$ state. We conclude, based on selection rules, that the primary decay route to $X ^1\Sigma^+(v=0)$ is a two-step cascade decay that leads to as much as $33\%$ branching into the $J=0$ rotational level. The experimental simplicity of our scheme opens up the possibility of easier access to the study and manipulation of ultracold heteronuclear molecules in the rovibronic ground state.