Manipulating the motion of polar molecules with microwave radiation

Abstract

Microwave radiation coupled into a cylindrically symmetric resonator is used to focus, guide, decelerate, and accelerate ammonia molecules in high-field-seeking states. In a first series of measurements, we demonstrate that the focal length of a microwave lens is directly proportional to the molecules’ velocity and to the inverse of the fourth root of the microwave power. In a second series of measurements employing a modified set-up, we use a multi-stage decelerator exploiting the TE_1,1,12 mode of a cylindrical resonator and various switching schemes. We can deliberately choose between spatial focusing and velocity focusing while guiding, and we demonstrate kinetic energy reduction by as much as 30% of a 12 m/s slow packet of molecules utilising the 12 deceleration stages.

Keywords:

• cold molecules
• microwave deceleration
• ac Stark effect

Acknowledgements

We thank Jens–Uwe Grabow, Boris Sartakov, and Wolfgang Jäger for helpful scientific discussions on various topics. This work has been supported by the ERC–2009–AdG programme under grant agreement 247142–MolChip, and the support of the Fonds der Chemischen Industrie via a Dozentenstipendium (MS).