High-Resolution Spectroscopy of $^{173}$Yb$^{+}$ Ions

TL;DR

This paper reports high-resolution spectroscopy of a single trapped $^{173}$Yb$^{+}$ ion, revealing a new electric quadrupole transition, precise isotope shift, hyperfine structure, and nuclear magnetic octupole moment with unprecedented accuracy.

Contribution

The study provides the first detailed spectroscopic characterization of $^{173}$Yb$^{+}$, including a new transition, isotope shift, and hyperfine measurements, advancing quantum physics and atomic clock research.

Findings

Observation of a new 436 nm electric quadrupole transition.

Precise measurement of isotope shift with 1.4 Hz uncertainty.

Determination of nuclear magnetic octupole moment with reduced uncertainty.

Abstract

Compared to other stable isotopes of $\rm{Yb}^+$, $^{173}\rm{Yb}^+$ has a richer hyperfine structure, which leads to more favorable clock transitions, spectroscopic techniques for probing new physics, and more sophisticated quantum computing architectures. However, to date, its electronic spectrum remains poorly characterized. Here, we report on efficient laser cooling, state preparation, and detection of a single trapped $^{173}\rm{Yb}^+$ ion. The previously unobserved $^2\!S_{1/2} \rightarrow {}^2\!D_{3/2}$ electric quadrupole transition at 436 nm is coherently excited, and the isotope shift between $^{171}\rm{Yb}^+$ and $^{173}\rm{Yb}^+$ on this transition is determined with an uncertainty of 1.4 Hz. Using microwave spectroscopy, we resolve the hyperfine structure (HFS) of the ${}^2\!D_{3/2}$ state with a relative uncertainty below $10^{-8}$. From the HFS measurement data, we infer for ${}^{173}$Yb a nuclear magnetic octupole moment $\Omega = -0.062(8)\,({\rm b} \times \mu_N)$ with uncertainty reduced by more than 2 orders of magnitude compared to previous studies. The data also allow us to determine hyperfine anomalies for the ${}^2\!S_{1/2}$ and ${}^2\!D_{3/2}$ states.