Double Bragg diffraction: A tool for atom optics

TL;DR

This paper explores double Bragg diffraction in atom interferometry, demonstrating its advantages for noise reduction and providing analytical solutions beyond the deep Bragg regime validated by numerical comparisons.

Contribution

It extends double-diffraction techniques to Bragg transitions, developing an analytical approach using the method of averaging for complex off-resonant interactions.

Findings

Automatic doubling of momentum transfer in symmetric configurations

Analytical results beyond the deep Bragg regime

Validation through numerical simulations

Abstract

The use of retro-reflection in light-pulse atom interferometry under microgravity conditions naturally leads to a double-diffraction scheme. The two pairs of counterpropagating beams induce simultaneously transitions with opposite momentum transfer that, when acting on atoms initially at rest, give rise to symmetric interferometer configurations where the total momentum transfer is automatically doubled and where a number of noise sources and systematic effects cancel out. Here we extend earlier implementations for Raman transitions to the case of Bragg diffraction. In contrast with the single-diffraction case, the existence of additional off-resonant transitions between resonantly connected states precludes the use of the adiabatic elimination technique. Nevertheless, we have been able to obtain analytic results even beyond the deep Bragg regime by employing the so-called "method of averaging," which can be applied to more general situations of this kind. Our results have been validated by comparison to numerical solutions of the basic equations describing the double-diffraction process.