A simple, passive design for large optical trap arrays for single atoms

TL;DR

This paper introduces a passive, cost-effective method for creating large 2D arrays of optical traps for single atoms using a novel 4f filtering scheme and custom masks, enabling high-density trapping with minimal out-of-focus interference.

Contribution

The authors develop a passive optical trapping approach with a novel filtering scheme and mask design, eliminating active components and reducing out-of-focus trapping effects in large atom arrays.

Findings

Successfully created a 1225-site dark trap array for Cs atoms.

Demonstrated mitigation of out-of-focus traps caused by the Talbot effect.

Achieved high-quality atom trapping using broadband laser light.

Abstract

We present an approach for trapping cold atoms in a 2D optical trap array generated with a novel 4f filtering scheme and custom transmission mask without any active device. The approach can be used to generate arrays of bright or dark traps, or both simultaneously with a single wavelength for forming two-species traps. We demonstrate the design by creating a 2D array of 1225 dark trap sites, where single Cs atoms are loaded into regions of near-zero intensity in an approximately Gaussian profile trap. Moreover, we demonstrate a simple solution to the problem of out-of-focus trapped atoms, which occurs due to the Talbot effect in periodic optical lattices. Using a high power yet low cost spectrally and spatially broadband laser, out-of-focus interference is mitigated, leading to near perfect removal of Talbot plane traps.