Formation of ultracold polar molecules in the rovibrational ground state

TL;DR

This paper reports the formation of ultracold LiCs molecules in the rovibrational ground state using photo-association, demonstrating selective state production and characterization methods, enabling large samples of cold dipolar molecules.

Contribution

It introduces a single photo-association method to produce ultracold ground state molecules with high rate and state selectivity, along with spectroscopic characterization techniques.

Findings

Production rate of up to 5x10^3 molecules/sec

Selective creation of v''=0, J''=2 molecules with 50-fold higher rate

Determination of rotational and vibrational states using spectroscopy

Abstract

Ultracold LiCs molecules in the absolute ground state X$^1\Sigma^+$, v"=0, J"=0 are formed via a single photo-association step starting from laser-cooled atoms. The selective production of v"=0, J"=2 molecules with a 50-fold higher rate is also demonstrated. The rotational and vibrational state of the ground state molecules is determined in a setup combining depletion spectroscopy with resonant-enhanced multi-photon ionization time-of-flight spectroscopy. Using the determined production rate of up to 5x10^3 molecules/s, we describe a simple scheme which can provide large samples of externally and internally cold dipolar molecules.