Cold collision and high-resolution spectroscopy of buffer gas cooled BaF Molecule

TL;DR

This paper presents a detailed experimental study of buffer gas cooling and high-resolution spectroscopy of BaF molecules, demonstrating effective cooling and providing a benchmark for future laser cooling applications.

Contribution

It reports the first detailed collision cross section measurement and high-resolution spectral data for BaF, advancing the understanding of buffer gas cooling for this molecule.

Findings

Collision cross section measured as 1.4(7)×10^{-14} cm^2

Efficient cooling of rotational and vibrational states achieved

Identification of laser cooling transition for BaF

Abstract

We reported a detailed experimental study of the cold collision of Barium monofluoride (BaF) with buffer gas and the high-resolution spectroscopy relevant with direct laser cooling. BaF molecules are efficiently produced with laser ablation and buffer-gas cooled in a cryogenic apparatus. The laser cooling relevant transition $|X^2\Sigma, v=0, N=1\rangle$ to $|A^2\Pi, v'=0, J'=1/2\rangle$ is identified. The collision cross section with buffer gas is measured to be $1.4(7)\times10^{-14} cm^{-2}$, which is very suitable for buffer gas cooling. Both rotational and vibrational temperatures are effectively cooled, and large mount of molecules are quenched into the desired states. Our study provides an important benchmark for further laser cooling of BaF molecule.