Characterizing the Zeeman slowing force for $^{40}$Ca$^{19}$F molecules

TL;DR

This study explores the feasibility of Zeeman slowing for CaF molecules, measuring hyperfine spectra, analyzing scattering rates, and demonstrating potential for effective molecular slowing and trapping.

Contribution

It provides the first detailed measurement and analysis of Zeeman slowing forces for CaF molecules, including experimental spectra and force profile simulations.

Findings

Hyperfine spectrum matches theoretical predictions

Calculated scattering rates enable force profile estimation

Simulations show effective slowing and compression of molecules

Abstract

In this paper we investigate the feasibility of Zeeman slowing calcium monofluoride (CaF) molecules originating from a cryogenic buffer gas cell. We measure the $A^2\Pi_{1/2} (v=0, J=\frac{1}{2}) - X^2\Sigma_{1/2} (v=0, N=1)$ hyperfine spectrum of CaF in the Paschen-Back regime and find excellent agreement with theory. We then investigate the scattering rate of the molecules in a molecular Zeeman slower by illuminating them with light from a 10mW broad repumper and a 10mW multi-frequency slowing laser. By comparing our results to theory we can calculate the photon scattering rate at higher powers, leading to a force profile for Zeeman slowing. We show results from a simple 1D simulation demonstrating that this force is both strong and narrow enough to lead to significant compression, and slowing of the molecules to trappable velocities.