Accurate prediction and measurement of vibronic branching ratios for laser cooling linear polyatomic molecules

TL;DR

This paper introduces a combined computational and experimental method to accurately measure vibronic branching ratios in linear polyatomic molecules, achieving unprecedented sensitivity crucial for laser cooling applications.

Contribution

It presents a new approach that significantly improves the precision of branching ratio measurements, enabling better control of molecular states for laser cooling.

Findings

Achieved measurement sensitivity at the 10^{-5} level.

Demonstrated methods on CaOH and YbOH molecules.

Enhanced understanding of vibronic transitions for laser cooling.

Abstract

We report a generally applicable computational and experimental approach to determine vibronic branching ratios in linear polyatomic molecules to the $10^{-5}$ level, including for nominally symmetry forbidden transitions. These methods are demonstrated in CaOH and YbOH, showing approximately two orders of magnitude improved sensitivity compared with the previous state of the art. Knowledge of branching ratios at this level is needed for the successful deep laser cooling of a broad range of molecular species.