Multi-frequency telecom fibered laser system for potassium laser cooling

TL;DR

This paper presents a compact, multi-frequency fibered laser system for potassium atom cooling, achieving high atom numbers and low temperatures, suitable for portable ultracold atom experiments.

Contribution

It introduces a novel fiber-based multi-frequency laser system with efficient frequency doubling for potassium cooling, enabling high atom numbers and rapid loading.

Findings

Trapped up to 4 billion $^{41}$K atoms.

Achieved sub-Doppler temperatures of 16 μK.

Fast loading time of 2.5 seconds.

Abstract

We describe a compact and versatile multi-frequency laser system for laser-cooling potassium atoms, by frequency doubling a fiber-optic telecom beam ($\simeq 1534$ or $1540$~nm). Low-power fiber-based telecom lasers and components generate a single beam containing the cooling and repumper half frequencies, subsequently amplified by high-power amplifier. A final free-space SHG stage generates a single beam with typically 2.5 W at quasi-resonant frequencies ($\simeq 767$ or $770$~nm) with high-quality mode and ready for laser cooling. This allowed to trap up to $4\times10^9$ $^{41}$K atoms with fast loading times (2.5 s) at sub-Doppler temperatures of 16~$\mu$K. This opens promising perspectives towards versatile and transportable ultracold atom setups.