A momentum filter for atomic gas

TL;DR

This paper introduces a momentum filter for atomic gases using a Talbot-Lau interferometer, effectively narrowing the momentum distribution and applicable to both condensate and non-condensed cold atoms.

Contribution

The paper presents a novel momentum filtering technique based on a Talbot-Lau interferometer, demonstrating rapid momentum purification in atomic gases.

Findings

Significant reduction in momentum width of atomic gases.

Good agreement between theory and experiment.

Effective for both condensate and non-condensed atoms.

Abstract

We propose and demonstrate a momentum filter for atomic gas based on a designed Talbot-Lau interferometer. It consists in two identical optical standing wave pulses separated by a delay equal to odd multiples of the half Talbot time. The one dimensional momentum width along the long direction of a cigar shape condensate is rapidly and greatly purified to a minimum, which corresponds to the ground state energy of the confining trap in our experiment. We find good agreement between theoretical analysis and experimental results. The filter is also effective for non-condensed cold atoms and could be applied widely.