Laser cooled 137BaF molecules for measuring nuclear-spin-dependent parity violation

TL;DR

This paper reports the successful laser cooling of 137BaF molecules, enabling their use in precision measurements of nuclear-spin-dependent parity violation, with implications for probing weak interactions.

Contribution

It demonstrates optical cycling and laser cooling of 137BaF molecules, overcoming complex level structures for advanced quantum control in fundamental physics experiments.

Findings

Achieved optical cycling with up to 112 levels involved

Demonstrated transverse laser cooling of 137BaF molecules

Enabled potential for high-precision parity violation measurements

Abstract

We demonstrate optical cycling and transverse laser cooling of a beam of fermionic 137BaF molecules. Their high masses and nuclear spins make these molecules sensitive probes for parity violation and properties of the weak interaction. However, the nuclear spins also lead to a quasi-closed cycling transition currently involving up to 112 levels, which significantly exceeds the complexity in other laser-cooled molecules. Optical cycling and cooling are facilitated through carefully designed optical spectra tailored to this molecular structure. Our results pave the way for efficient state preparation, detection, and cooling in precision measurements using this species and other similar species.