Laser cooling of rotation and vibration by optical pumping

TL;DR

This paper discusses a method for cooling molecules to their lowest rotational and vibrational states using optical pumping, with experimental and theoretical insights to enhance control over molecular internal states.

Contribution

It introduces a combined experimental and theoretical approach for rovibrational cooling of molecules, advancing control over molecular quantum states.

Findings

Successful cooling of Cs2 molecules to rovibrational ground state

Development of excitation schemes and detection techniques

Theoretical analysis explaining experimental results

Abstract

We have recently demonstrated that optical pumping methods combined with photoassociation of ultra-cold atoms can produce ultra-cold and dense samples of molecules in their absolute rovibronic ground state. More generally, both the external and internal degrees of freedom can be cooled by addressing selected rovibrational levels on demand. Here, we recall the basic concepts and main steps of our experiments, including the excitation schemes and detection techniques we use to achieve the rovibrational cooling of Cs2 molecules. In addition, we present the determination of formation pathways and a theoretical analysis explaining the experimental observations. These simulations improves the spectroscopic knowledge required to transfer molecules to any desired rovibrational level.