Observation of the $^1$S$_0$ to $^3$D$_1$ clock transition in $^{175}$Lu$^+$

TL;DR

This paper reports the first laser spectroscopy of a specific clock transition in $^{175}$Lu$^+$, demonstrating clock operation and precise measurement of hyperfine intervals with high accuracy.

Contribution

It presents the first observation and measurement of the $^1$S$_0$ to $^3$D$_1$ transition in $^{175}$Lu$^+$, including hyperfine intervals and state lifetime with unprecedented precision.

Findings

Hyperfine intervals measured with 10 ppb uncertainty

Optical frequency averaged over hyperfine transitions determined

State lifetime inferred to be approximately 174 hours

Abstract

We report the first laser spectroscopy of the $^1$S$_0$ to $^3$D$_1$ clock transition in $^{175}$Lu$^+$. Clock operation is demonstrated on three pairs of Zeeman transitions, one pair from each hyperfine manifold of the $^3$D$_1$ term. We measure the hyperfine intervals of the $^3$D$_1$ to 10 ppb uncertainty and infer the optical frequency averaged over the three hyperfine transitions to be 353.639 915 952 2 (6) THz. The lifetime of the $^3$D$_1$ state is inferred to be $174^{+23}_{-32}$ hours from the M1 coupling strength.