High-resolution atom interferometers with suppressed diffraction phases

TL;DR

This paper presents a method to significantly reduce diffraction phases in atom interferometers, enhancing their sensitivity and precision for fundamental constant measurements.

Contribution

The authors demonstrate a combined approach using Bragg diffraction and Bloch oscillations to null diffraction phases, achieving a 1500-fold reduction and high-contrast interferometry.

Findings

1500-fold reduction of diffraction phase

High contrast with up to 4.4 million radians phase difference

Resolution of the fine structure constant at 0.25 ppb in 25 hours

Abstract

We experimentally and theoretically study the diffraction phase of large-momentum transfer beam splitters in atom interferometers based on Bragg diffraction. We null the diffraction phase and increase the sensitivity of the interferometer by combining Bragg diffraction with Bloch oscillations. We demonstrate agreement between experiment and theory, and a 1500-fold reduction of the diffraction phase, limited by measurement noise. In addition to reduced systematic effects, our interferometer has high contrast with up to 4.4 million radians of phase difference, and a resolution in the fine structure constant of $\delta \alpha/\alpha=0.25\,$ppb in 25 hours of integration time.