Diffusing-Wave Spectroscopy of Cold Atoms in Ballistic Motion

TL;DR

This paper applies diffusing-wave spectroscopy to cold atoms in ballistic motion, analyzing the transition from single to multiple scattering regimes and comparing experimental results with theoretical models.

Contribution

It introduces the use of diffusing-wave spectroscopy for cold atoms in ballistic motion and compares experimental data with phase-coherent and incoherent models.

Findings

Intensity correlation function transitions from Gaussian to complex decay.

Sample temperature can be inferred from the Gaussian width.

Good agreement between experiments and models.

Abstract

Diffusing-wave spectroscopy is a powerful technique which consists in measuring the temporal correlation function of the intensity of light multiply scattered by a medium. In this paper, we apply this technique to cold atoms under purely ballistic motion and we investigate the transition between the single and the multiple scattering regime. The intensity correlation function changes from a simple Gaussian function, whose width reveals the sample temperature, to a more complex decay shortened by the frequency redistribution in the thick cloud. These features are quantitatively compared to simulations with a phase-coherent and an incoherent model. Both show a very good agreement with the experiments.