A Simple, Versatile Laser System for the Creation of Ultracold Ground State Molecules

TL;DR

This paper presents a simple, versatile laser system that narrows linewidths for creating ultracold ground state molecules, enabling efficient STIRAP transfer demonstrated with 87Rb133Cs molecules.

Contribution

A single fixed-length optical cavity system is used to simultaneously narrow and tune two lasers for STIRAP in ultracold molecule creation, simplifying the process.

Findings

Laser linewidths reduced to several hundred Hz

Successful molecular spectroscopy of 87Rb133Cs

Efficient transfer to rovibrational ground state via STIRAP

Abstract

A narrow-linewidth, dual-wavelength laser system is vital for the creation of ultracold ground state molecules via stimulated Raman adiabatic passage (STIRAP) from a weakly bound Feshbach state. Here we describe how a relatively simple apparatus consisting of a single fixed-length optical cavity can be used to narrow the linewidth of the two different wavelength lasers required for STIRAP simultaneously. The frequency of each of these lasers is referenced to the cavity and is continuously tunable away from the cavity modes through the use of non-resonant electrooptic modulators. Self-heterodyne measurements suggest the laser linewidths are reduced to several hundred Hz. In the context of 87Rb133Cs molecules produced via magnetoassociation on a Feshbach resonance, we demonstrate the performance of the laser system through one- and two-photon molecular spectroscopy. Finally, we demonstrate transfer of the molecules to the rovibrational ground state using STIRAP.