Double diffraction in an atomic gravimeter

TL;DR

This paper introduces a novel double diffraction scheme for cold atom gravimetry that enhances measurement stability and reduces systematics, achieving high sensitivity with simplified setup.

Contribution

It presents a new double diffraction technique for atomic gravimeters that remains effective with non-zero atom velocities, improving robustness and accuracy.

Findings

Achieved a sensitivity of 1.2×10⁻⁷g per shot.

Demonstrated an interferometer insensitive to laser phase noise.

Reduced technical complexity of atomic gravimetry.

Abstract

We demonstrate the realization of a new scheme for cold atom gravimetry based on the use of double diffraction beamsplitters recently demonstrated in \cite{Leveque}, where the use of two retro-reflected Raman beams allows symmetric diffraction in $\pm \hbar k_{eff}$ momenta. Though in principle restricted to the case of zero Doppler shift, for which the two pairs of Raman beams are simultaneously resonant, we demonstrate that such diffraction pulses can remain efficient on atoms with non zero velocity, such as in a gravimeter, when modulating the frequency of one of the two Raman laser sources. We use such pulses to realize an interferometer insensitive to laser phase noise and some of the dominant systematics. This reduces the technical requirements and would allow the realization of a simple atomic gravimeter. We demonstrate a sensitivity of $1.2\times10^{-7}g$ per shot.