Photoassociation of a Quantum Degenerate Gas

TL;DR

This paper reports measurements of photoassociation rates and frequency shifts in a quantum degenerate 7Li gas, confirming theoretical predictions and identifying saturation mechanisms at high laser intensities.

Contribution

The study provides experimental validation of quantum mechanical unitarity as the saturation mechanism in photoassociation of a quantum degenerate gas.

Findings

Rate increases linearly at low intensities

Saturation occurs at higher intensities

Measured rates agree with theoretical predictions

Abstract

We have measured the intensity dependent rate and frequency shift of a photoassociation transition in a quantum degenerate gas of 7Li. The rate increases linearly with photoassociation laser intensity for low intensities, whereas saturation is observed at higher intensities. The measured rates and shifts agree reasonably well with theory within the estimated systematic uncertainties. Several theoretically predicted saturation mechanisms are discussed, but a theory in which saturation arises because of quantum mechanical unitarity agrees well with the data.