Rotational state detection of electrically trapped polyatomic molecules

Rosa Glöckner,Alexander Prehn,Martin Zeppenfeld,Gerhard Rempe

doi:10.1088/1367-2630/17/5/055022

Rosa Glöckner, Alexander Prehn + Show 2 more

Open Access

https://doi.org/10.1088/1367-2630/17/5/055022

Copy DOI

Abstract

Detecting the internal state of polar molecules is a substantial challenge when standard techniques such as resonance-enhanced multiphoton ionization or laser-induced fluorescense do not work. As this is the case for most polyatomic molecule species, in this paper we investigate an alternative based on state-selective removal of molecules from an electrically trapped ensemble. Specifically, we deplete molecules by driving rotational and/or vibrational transitions to untrapped states. Fully resolving the rotational state with this method can be a considerable challenge, as the frequency differences between various transitions are easily substantially less than the Stark broadening in an electric trap. However, by using a unique trap design that provides homogeneous fields in a large fraction of the trap volume, we successfully discriminate all rotational quantum numbers, including the rotational M-substate.

Highlights

Cold and ultracold molecules offer a large variety of applications in quantum information [1,2,3], quantum simulation [4, 5], high-precision measurements [6,7,8], or for quantum chemistry and cold collision studies [9, 10]
In this paper we present a detailed investigation of a rotational state detection technique that is suitable for a large variety of molecular species, especially polyatomic molecular species
The symmetric top molecule Before discussing our rotational state detection, we briefly review the properties of symmetric top molecules

Summary

Introduction

Cold and ultracold molecules offer a large variety of applications in quantum information [1,2,3], quantum simulation [4, 5], high-precision measurements [6,7,8], or for quantum chemistry and cold collision studies [9, 10] Triggered by these prospects, in recent years an immense effort has focused on the development of methods for the production of cold and ultracold molecules. Buffer gas cooling [14,15,16,17], deceleration after (e.g., supersonic expansion [18,19,20,21,22,23,24,25,26]), and velocity filtering [27, 28] are widely applicable These methods are mainly suited to prepare ensembles above temperatures of about 10 mK. Prospects for direct cooling to ultracold temperatures have recently appeared in the form of laser cooling of molecules [29,30,31,32,33]

Methods

Results

Conclusion