Effective velocity distribution in an atom gravimeter: effect of the convolution with the response of the detection

TL;DR

This paper investigates how the detection response affects the effective velocity distribution of atoms in a free-fall gravimeter, revealing asymmetries that influence bias averaging due to Coriolis acceleration.

Contribution

It provides a detailed analysis of the convolution effect of detection response on the velocity distribution, enhancing understanding of bias effects in atom gravimeters.

Findings

Detection response causes asymmetry in effective velocity distribution.

Initial atomic sample position influences velocity distribution asymmetry.

Convolution with detection significantly impacts Coriolis bias averaging.

Abstract

We present here a detailed study of the influence of the transverse motion of the atoms in a free-fall gravimeter. By implementing Raman selection in the horizontal directions at the beginning of the atoms free fall, we characterize the effective velocity distribution, ie the velocity distribution of the detected atom, as a function of the laser cooling and trapping parameters. In particular, we show that the response of the detection induces a pronounced asymetry of this effective velocity distribution that depends not only on the imbalance between molasses beams but also on the initial position of the displaced atomic sample. This convolution with the detection has a strong influence on the averaging of the bias due to Coriolis acceleration. The present study allows a fairly good understanding of results previously published in {\it Louchet-Chauvet et al., NJP 13, 065025 (2011)}, where the mean phase shift due to Coriolis acceleration was found to have a sign different from expected.