Photoassociation of Ultracold Atoms: A New Spectroscopic Technique

Daniel J. Heinzen, Joseph D. Miller, Robert A. Cline

Olivier Dulieu, Jesús Pérez‐Ríos, Maxence Lepers

Paul D. Lett

Research into collisions at ultracold temperatures has revealed new physics and created new spectroscopic techniques. A brief review of ultracold collisions in general and an overview of photoassociation experiments with laser‐cooled Na atoms are given here. These experiments point out some of the interesting and unique features of ultracold collisions and some of the possibilities for their application in high resolution spectroscopy and the manipulation of atomic collisions.

Steven Moal, M. Portier, J. Kim +2 more

We report a new method to detect photoassociation (PA) resonance signals through the collective dipole oscillations produced by a momentum transfer from the PA excitation lasers to an ultracold atomic cloud confined by a magnetic trap. Using the amplitudes of these oscillations for several molecular excited states, we derive a precise value for the s -wave scattering length between the ultracold atoms. This new and simple method provides results in excellent agreement with previous spectroscopic PA measurements based on atom losses or temperature rise. We present a simple model interpreting the momentum and energy transferred from the PA process to trap confined ultracold atoms.

Randall G. Hulet

Keith R. Burnett

Our ability to study the interactions between atoms at ultracold temperatures has undergone little short of a revolution in recent years. This is largely due to the development of spectroscopic techniques that can probe the properties of laser-cooled atoms with high precision. One of these techniques is photoassociation, and a group at the National Institute of Standards and Technology (NIST) in Maryland, US, has now used this method to obtain new information about the interactions between atoms in molecules. The NIST researchers used lasers to produce and probe pairs of sodium atoms that were bound together in very long-range molecular states (K M Jones et al. 1997 J. Phys. B.30289).