Single-laser, one beam, tetrahedral magneto-optical trap

TL;DR

This paper presents a novel tetrahedral magneto-optical trap using a single laser beam and three mirrors, enabling efficient atom trapping with improved geometry and potential applications in quantum gases and microfabrication.

Contribution

The authors demonstrate a 4-beam pyramidal MOT with a simplified mirror setup, offering enhanced trapping efficiency and geometric flexibility compared to standard designs.

Findings

Optimum mirror angles for trapping efficiency identified

Supra-plane pyramid MOT configuration successfully demonstrated

The scheme allows extension to a 2-beam refractive system

Abstract

We have realised a 4-beam pyramidal magneto-optical trap ideally suited for future microfabrication. Three mirrors split and steer a single incoming beam into a tripod of reflected beams, allowing trapping in the four-beam overlap volume. We discuss the influence of mirror angle on cooling and trapping, finding optimum efficiency in a tetrahedral configuration. We demonstrate the technique using an ex-vacuo mirror system to illustrate the previously inaccessible supra-plane pyramid MOT configuration. Unlike standard pyramidal MOTs both the pyramid apex and its mirror angle are non-critical and our MOT offers improved molasses free from atomic shadows in the laser beams. The MOT scheme naturally extends to a 2-beam refractive version with high optical access. For quantum gas experiments, the mirror system could also be used for a stable 3D tetrahedral optical lattice.