Isotopologue-selective laser cooling of molecules

TL;DR

This paper demonstrates the first isotopologue-selective laser cooling of molecules, enabling precise manipulation of specific isotopic variants, which advances molecular control for applications like trace analysis and fundamental physics tests.

Contribution

It introduces a method for isotopologue-selective laser cooling of molecules, specifically using BaF, a novel capability not previously achieved in molecular laser cooling.

Findings

Successful cooling of 136BaF isotopologue within a mixed molecular beam.

Enables high-fidelity detection of low-abundance isotopologues.

Facilitates development of isotopologue-specific molecular trapping.

Abstract

Direct laser cooling of molecules has made significant progress in recent years. However, the selective cooling and manipulation of molecules based on their isotopic composition, which is ubiquitous in atomic laser cooling, has not yet been achieved. Here, we demonstrate such isotopologue-selective laser cooling of molecules, using barium monofluoride (BaF) as an example. The manipulation of the rare and previously uncooled 136BaF is achieved within a molecular beam containing several isotopologues of significantly higher natural abundance. Our results enable intense molecular beams and high fidelity detection of select low-abundance isotopologues or isotopic mixtures. Such beams are a first step towards isotopologue-selective molecular trapping and will be useful for applications in trace gas analysis, cold chemistry and precision tests of fundamental symmetries.