Simplified landscapes for optimization of shaken lattice interferometry

TL;DR

This paper demonstrates how phase-modulated optical lattices can be used to split atom clouds into specific momentum states, optimizing the process through simple models, simulations, experiments, and genetic algorithms for improved atom interferometry.

Contribution

It introduces a simple analytic model for atom splitting in shaken lattices and applies genetic algorithms to optimize splitting efficiency at specific momentum states.

Findings

Single-frequency shaking achieves $oxed{ ext{±}2 ext{ħ}k_L}$ splitting.

Phase control allows for phase-dependent splitting outcomes.

Optimization reaches approximately 0.1% accuracy for certain momentum states.

Abstract

Motivated by recent results using shaken optical lattices to perform atom interferometry, we explore splitting of an atom cloud trapped in a phase-modulated ("shaken") optical lattice. Using a simple analytic model we are able to show that we can obtain the simplest case of $\pm2\hbar k_\mathrm{L}$ splitting via single-frequency shaking. This is confirmed both via simulation and experiment. Furthermore, we are able to split with a relative phase $\theta$ between the two split arms of $0$ or $\pi$ depending on our shaking frequency. Addressing higher-order splitting, we determine that $\pm6\hbar k_\mathrm{L}$ splitting is sufficient to be able to accelerate the atoms in counter-propagating lattices. Finally, we show that we can use a genetic algorithm to optimize $\pm4\hbar k_\mathrm{L}$ and $\pm6\hbar k_\mathrm{L}$ splitting to within $\approx0.1\%$ by restricting our optimization to the resonance frequencies corresponding to single- and two-photon transitions between Bloch bands.