Proof-of-principle demonstration of vertical gravity gradient measurement using a single proof mass double-loop atom interferometer

TL;DR

This paper demonstrates a proof-of-principle for measuring Earth's gravity gradient using a single atom interferometer with cold rubidium atoms, showcasing a simple and robust setup suitable for onboard applications.

Contribution

It introduces a novel double-loop atom interferometer configuration capable of directly measuring gravity gradients with immunity to rotation effects.

Findings

Successful gravity gradient measurement with and without seismic isolation.

Demonstrated immunity to rotation-induced contrast loss.

Potential for onboard gravity gradient sensing applications.

Abstract

We demonstrate a proof-of-principle of direct Earth gravity gradient measurement with an atom interferometer-based gravity gradiomter using a single proof mass of cold 87 rubidium atoms. The atomic gradiometer is implemented in the so-called double-loop configuration, hence providing a direct gravity gradient dependent phase shift insensitive do DC acceleration and constant rotation rate. The atom interferometer (AI) can be either operated as a gravimeter or a gradiomter by simply adding an extra Raman $\pi$-pulse. We demonstrate gravity gradient measurements first using a vibration isolation platform and second without seismic isolation using the correlation between the AI signal and the vibration signal measured by an auxilliary classical accelerometer. The simplicity of the experimental setup (a single atomic source and unique detection) and the immunity of the AI to rotation-induced contrast loss, make it a good candidate for onboard gravity gradient measurements.