Characterizing the Zeeman slowing force for 40Ca19F molecules

Abstract

In this paper we investigate the feasibility of Zeeman slowing calcium monofluoride 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 10 mW broad repumper and a 10 mW 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 narrow enough in velocity space to lead to significant velocity compression, and slowing of the molecules to trappable velocities.

Keywords

• cold molecules
• Zeeman slower
• spectroscopy