Phase shift in an atom interferometer induced by the additional laser lines of a Raman laser generated by modulation

TL;DR

This paper analyzes how additional laser lines from a modulated Raman laser induce phase shifts in atom interferometers, affecting their precision, and proposes ways to mitigate these effects for more accurate measurements.

Contribution

It provides a precise calculation model for phase shifts caused by laser line sidebands and validates it experimentally, improving understanding of systematic effects in compact atom gravimeters.

Findings

Phase shift can be accurately modeled and predicted.

Experimental validation confirms the model's reliability.

Inaccuracy can be reduced with better control or configuration adjustments.

Abstract

The use of Raman laser generated by modulation for light-pulse atom interferometer allows to have a laser system more compact and robust. However, the additional laser frequencies generated can perturb the atom interferometer. In this article, we present a precise calculation of the phase shift induced by the additional laser frequencies. The model is validated by comparison with experimental measurements on an atom gravimeter. The uncertainty of the phase shift determination limits the accuracy of our compact gravimeter at 8.10^-8 m/s^2. We show that it is possible to reduce considerably this inaccuracy with a better control of experimental parameters or with particular interferometer configurations.