Free-space quantum interface of a single atomic tweezer array with light

TL;DR

This paper introduces a practical method to efficiently couple light with a 2D atomic tweezer array using a specially designed composite mode, enhancing quantum information processing capabilities.

Contribution

It proposes a novel composite mode generated from a single Gaussian beam that matches the array's diffraction pattern, improving coupling efficiency in quantum interfaces.

Findings

Coupling efficiency scales favorably with atom number, exceeding 0.99 for 149 atoms.

The scheme is compatible with standard optical objectives with NA <= 0.7.

The approach is robust against optical imperfections and atomic-position errors.

Abstract

We present a practical approach for interfacing light with a two-dimensional atomic tweezer array. Typical paraxial fields are poorly matched to the array's multi-diffraction-order radiation pattern, thus severely limiting the interface coupling efficiency. Instead, we propose to design a field mode that naturally couples to the array: it consists of a unique superposition of multiple beams corresponding to the array's diffraction orders. This composite mode can be generated from a single Gaussian beam using standard free-space optics, including spatial light modulators and a single objective lens. For a triangular array with lattice spacing about twice the wavelength, all diffraction angles remain below 35 degrees, making the scheme compatible with standard objectives of numerical aperture NA <= 0.7. Our analytical theory and scattering simulations reveal that the interface efficiency r0 for quantum information tasks scales favorably with the array atom number N: reaching >0.99 (>0.9999) for N = 149 (N approximately 1000) and scaling as 1 - r0 scales as 1/N for large N. The scheme is robust to optical imperfections and atomic-position errors, offering a viable path for quantum light-matter applications and state readout in current tweezer-array platforms.