Enhanced trapping of colding lithium by using the multiple-sideband cooling in a two-dimensional magneto-optical trap

TL;DR

This paper demonstrates a method to significantly increase lithium atom trapping efficiency in a 3D magneto-optical trap by employing multiple-sideband cooling in a 2D MOT, achieving four times more atoms than single-frequency cooling.

Contribution

The study introduces a novel multiple-sideband cooling technique in a 2D MOT to enhance lithium trapping efficiency in a 3D MOT, with experimental validation and theoretical analysis.

Findings

Achieved 4 times more trapped atoms with multiple-sideband cooling.

Good agreement between experimental results and two-level model predictions.

Identified the effectiveness of multiple-sideband cooling specifically for lithium.

Abstract

Trapping lithium with a big number in a simplified experimental setup has difficulties and challenges today. In this paper, we experimentally demonstrate the enhancement of \textsuperscript{6}Li trapping efficiency in a three-dimensional magneto-optical trap (3D MOT) by using the multiple-sideband cooling in a two-dimensional magneto-optical trap (2D MOT). To improve the number of trapped atoms, we broaden the cooling light spectrum to 102 MHz composed of seven frequency components and then trap atoms with a number of $6.0\times10^8$ which is about 4 times compared to that in the single-frequency cooling. The capture velocity and dependence of atomic number on the laser detuning have been analyzed, where the experimental result has a good agreement with the theoretical prediction based on a simple two-level model. We also analyze the loss rate of alkali metals due to fine-structure exchanging collisions and find that the multiple-sideband cooling is special valid for lithium.