Prospects for a Narrow Line MOT in YO

TL;DR

This paper explores the potential of using a narrow-line transition in YO molecules for advanced laser cooling, enabling lower temperatures and improved control over molecular samples.

Contribution

It introduces the feasibility of a narrow-line magneto-optical trap in YO, enhancing cooling techniques with minimal system modifications.

Findings

Narrow-line transition in YO has a linewidth of ~160 kHz.

Narrow-line cooling can reduce temperature from ~1 mK to ~10 μK.

The method requires minimal modifications to existing cooling setups.

Abstract

In addition to being suitable for laser cooling and trapping in a magneto-optical trap (MOT) using a relatively broad ($\sim$5 MHz) transition, the molecule YO possesses a narrow-line transition. This forbidden transition between the $X^{2}\Sigma$ and $A'^{2}\Delta_{3/2}$ states has linewidth $\sim$2$\pi\times$160 kHz. After cooling in a MOT on the $X^{2}\Sigma$ to $A^{2}\Pi_{1/2}$ (orange) transition, the narrow (red) transition can be used to further cool the sample, requiring only minimal additions to the first stage system. The narrow line cooling stage will bring the temperature from $\sim$1 mK to $\sim$10 $\mu$K, significantly advancing the frontier on direct cooling achievable for molecules.