Rotational state microwave mixing for laser cooling of complex diatomic molecules

TL;DR

This paper demonstrates a microwave-based rotational state mixing technique to enhance laser cooling of complex diatomic molecules, specifically yttrium monoxide, enabling the creation of slow molecular beams suitable for trapping.

Contribution

The authors introduce a novel microwave mixing method to facilitate optical cycling in complex molecules, advancing laser cooling capabilities beyond simpler species.

Findings

Successfully slowed YO molecules to below 10 m/s

Generated a measurable flux of slow YO molecules

Enabled direct loading into a magneto-optical trap

Abstract

We demonstrate the mixing of rotational states in the ground electronic state using microwave radiation to enhance optical cycling in the molecule yttrium (II) monoxide (YO). This mixing technique is used in conjunction with a frequency modulated and chirped continuous wave laser to slow longitudinally a cryogenic buffer gas beam of YO. We generate a measurable flux of YO below 10~m/s, directly loadable into a three-dimensional magneto-optical trap. This technique opens the door for laser cooling of molecules with more complex structure.