Addressable Rydberg excitation in arrays of single neutral atoms with a strongly focused flat-top beam

TL;DR

This paper introduces a method to generate flat-top laser beams for precise Rydberg excitation in neutral atom arrays, combining theoretical synthesis, numerical analysis, and experimental validation.

Contribution

It presents a novel approach to create flat-top beams using superpositions of Hermite-Gaussian or Laguerre-Gaussian modes, enabling improved spatial selectivity in Rydberg atom experiments.

Findings

Successful beam synthesis demonstrated experimentally.

Enhanced spatial selectivity confirmed by Rabi oscillation visibility.

Numerical analysis supports the effectiveness of the flat-top profile.

Abstract

We present a method for generating a laser beam with flat intensity and phase profiles in the focal region where the beam interacts with neutral $^{87}$Rb atoms in an array of optical dipole traps. We synthesize the beam as a superposition of Hermite--Gaussian or Laguerre--Gaussian modes. Then we give analytical expressions for the coefficients of such a superposition, an analysis of beam propagation along the $z$ axis in the vicinity of the waist, and several other related theoretical issues. Rydberg two-qubit dynamics driven by this flat-top profile are analyzed through numerical solutions of the Lindblad master equation using our in-house Julia package. Beam preparation is demonstrated on a neutral-atom experimental platform. Measurements reveal a difference in the visibility of Rabi oscillations for addressed atoms compared with neighboring ones, confirming the effective spatial selectivity provided by the flat-top beam profile.