Characterizing the Zeeman slowing force for 40Ca19F molecules

P Kaebert,M Siercke,S Ospelkaus,T Poll,M Petzold,S Xu,M Stepanova

doi:10.1088/1367-2630/ac1ed7

Abstract

In this paper we investigate the feasibility of Zeeman slowing calcium monofluoride molecules originating from a cryogenic buffer gas cell. We measure the 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.

Highlights

Owing to their internal degrees of freedom, molecular systems have the ability to probe fundamental physics and investigate states of matter dominated by long-range interactions
We have found excellent agreement both in position and height of the transition peaks compared to a rate equation model, with a measurement resolution of (9 ± 1) MHz
To measure the force a molecule would experience inside a type-II Zeeman slower we have measured the LIF signal of the molecules when subjected to 10 mW of light from a 120 MHz broad

Summary

Introduction

Owing to their internal degrees of freedom, molecular systems have the ability to probe fundamental physics and investigate states of matter dominated by long-range interactions. The ability to investigate these physical phenomena is directly linked to the number of molecules we can trap in experiments, as well as the temperatures to which we can cool them To this end, experiments on laser cooling molecules have had incredible success, realizing magneto-optical traps [1, 2, 3, 4, 5], molasses [6, 7, 8, 9, 10], magnetic [11, 12, 13] and electrostatic traps [14] as well as optical traps[10, 15, 6]. The slowing laser contains both σ+ and σ− polarizations and is frequency broadened by modulation of the laser current

Setup and Characterization of CaF transitions in the Paschen-Back regime

Measurement of the Zeeman slowing force

Zeeman Slowing Theory

Conclusion