Generation of high-purity, low-temperature samples of $^{39}$K for applications in metrology

TL;DR

This paper introduces an optical method to produce high-purity, low-temperature $^{39}$K samples suitable for precise metrology and matter-wave interferometry, demonstrating advanced gravimeter and spectrometer capabilities.

Contribution

The paper presents a novel all-optical technique for preparing ultra-cold, high-purity $^{39}$K samples in a magnetically-insensitive state, enabling enhanced metrological applications.

Findings

Achieved 95% purity in $^{39}$K samples at 6 μK temperature.

Realized an atomic gravimeter with state-of-the-art sensitivity.

Implemented a Ramsey-type spectrometer demonstrating high precision.

Abstract

We present an all optical technique to prepare a sample of $^{39}$K in a magnetically-insensitive state with 95\% purity while maintaining a temperature of 6 $\mu$K. This versatile preparation scheme is particularly well suited to performing matter-wave interferometry with species exhibiting closely-separated hyperfine levels, such as the isotopes of lithium and potassium, and opens new possibilities for metrology with these atoms. We demonstrate the feasibility of such measurements by realizing an atomic gravimeter and a Ramsey-type spectrometer, both of which exhibit a state-of-the-art sensitivity for cold potassium.