Robust Atom Interferometry with Double Bragg Diffraction

TL;DR

This work develops a comprehensive theoretical and numerical framework for high-contrast double Bragg diffraction atom interferometry, addressing limitations like contrast loss and imperfections to enable robust precision measurements in challenging environments.

Contribution

It introduces an analytic Hamiltonian model, a tri-frequency laser scheme with tunable detuning, and comprehensive simulations, advancing the robustness and accuracy of double Bragg atom interferometers.

Findings

Near-ideal beam-splitter and mirror performance with detuning control

Robust contrast achieved across experimental imperfections

Full 3D simulations reveal transverse effects and polarization distortions

Abstract

This thesis develops a general theoretical and numerical framework for achieving high-contrast atom interferometry based on double Bragg diffraction (DBD). While DBD offers intrinsic symmetry, reduced sensitivity to internal-state systematics, and suitability for microgravity experiments, its performance has long been limited by imperfect diffraction and contrast loss. This work overcomes these limitations by constructing an analytic Hamiltonian description of DBD -- including Doppler effects and polarization imperfections -- and by deriving reduced two- and five-level models via a truncated Magnus-expansion approach. These models clarify the origin of AC-Stark shifts, polarization-induced errors, and Doppler selectivity, and they provide accurate predictions for realistic input momentum distributions. Building on this theoretical foundation, the thesis introduces a tri-frequency laser scheme with dynamically tunable detuning and evaluates different detuning-control strategies using a five-level S-matrix formalism. Linear detuning sweeps and optimal-control pulses are shown to provide near-ideal beam-splitter and mirror performance, respectively, ensuring robust contrast across a wide range of experimental imperfections. Complementary full three-dimensional simulations using the GPU-accelerated Universal Atom Interferometer Simulator (UATIS) incorporate interacting Bose-Einstein condensates and realistic optical potentials, revealing transverse effects and polarization-induced distortions that extend the predictions of the one-dimensional non-interacting models. Taken together, this thesis establishes a coherent theoretical and numerical framework demonstrating that, with appropriate detuning control, double-Bragg atom interferometers can achieve the robustness required for precision inertial sensing and future space-based quantum tests of fundamental physics.