Precision spectroscopy of a trapped $^{173}$Yb$^+$ ion using a bath of ultracold atoms

TL;DR

This paper demonstrates a novel method for precision laser spectroscopy of trapped $^{173}$Yb$^+$ ions using ultracold atoms for cooling, achieving higher accuracy and potential for studying complex ions.

Contribution

Introduces a new technique coupling ultracold atoms with trapped ions for non-direct laser cooling and high-precision spectroscopy.

Findings

Measured hyperfine interaction constants with 6-9 times higher precision.

Successfully detected laser excitation via state-selective charge transfer.

Demonstrated applicability to ions with complex level structures.

Abstract

We demonstrate precision laser spectroscopy of a trapped $^{173}$Yb$^+$ ion that is not directly laser cooled by coupling it to ultracold atoms. The atomic bath continuously cools the internal degrees of freedom of the ion to its hyperfine ground state via spin-exchange collisions. Successful laser excitation is detected via state-selective charge transfer and subsequent ion loss. We probe the $6^2S_{1/2}\rightarrow 6^2P_{3/2}$ transition at 329 nm and measure the magnetic and electric hyperfine interaction constants for the $6^2P_{3/2}$ state to be $A=-241(1)$ MHz and $B=1460(8)$ MHz, respectively. Our results are in agreement with a previous measurement obtained in a hollow-cathode discharge experiment but are a factor of 6-9 more precise. The techniques demonstrated in this work may be extended to perform precision spectroscopy on other ions with complex level structures.