Cooperative scattering measurement of coherence in a spatially modulated Bose gas

TL;DR

This paper uses superradiant scattering to measure and analyze the coherence properties of a Bose gas in an optical lattice, revealing spatial correlations through temporal gain oscillations.

Contribution

It introduces a method to characterize first order spatial correlations in a Bose gas via superradiant scattering and mode competition analysis.

Findings

Observed periodical oscillations in superradiant gain.

Damped oscillations used to measure spatial coherence.

Achieved spatial correlation measurement with one lattice period precision.

Abstract

Correlations of a Bose gas released from an optical lattice are measured using superradiant scattering. Conditions are chosen so that after initial incident light pumping at the Bragg angle for diffraction, due to matter wave amplification and mode competition, superradiant scattering into the Bragg diffracted mode is preponderant. A temporal analysis of the superradiant scattering gain reveals periodical oscillations and damping due to the initial lack of coherence between lattice sites. Such damping is used for characterizing first order spatial correlations in our system with a precision of one lattice period.