Spectroscopy of the $^2S_{1/2} \rightarrow\,^2P_{3/2}$ transition in Yb II: Isotope shifts, hyperfine splitting and branching ratios

TL;DR

This paper presents highly precise spectroscopic measurements of the Yb+ ion transitions, isotope shifts, hyperfine splittings, and branching ratios, providing new experimental data that challenge existing theoretical predictions.

Contribution

The study offers the most precise measurements to date of isotope shifts, hyperfine constants, and branching ratios for Yb+ ions, revealing discrepancies with theoretical models.

Findings

Measured isotope shifts for all stable Yb+ isotopes except 173Yb+

Determined hyperfine constant A(2P3/2) = 875.4(10) MHz, deviating from theory

Found branching fractions of 0.17% and 1.08% for specific decay channels

Abstract

We report on spectroscopic results on the $^2S_{1/2} \rightarrow\,^2P_{3/2}$ transition in single trapped Yb$^+$ ions. We measure the isotope shifts for all stable Yb$^+$ isotopes except $^{173}$Yb$^+$, as well as the hyperfine splitting of the $^2P_{3/2}$ state in $^{171}$Yb$^+$. Our results are in agreement with previous measurements but are a factor of 5-9 more precise. For the hyperfine constant $A\left(^2P_{3/2}\right) = 875.4(10)$ MHz our results also agree with previous measurements but deviate significantly from theoretical predictions. We present experimental results on the branching ratios for the decay of the $^2P_{3/2}$ state. We find branching fractions for the decay to the $^2D_{3/2}$ state and $^2D_{5/2}$ state of 0.17(1)% and 1.08(5)%, respectively, in rough agreement with theoretical predictions. Furthermore, we measured the isotope shifts of the $^2F_{7/2} \rightarrow\,^1D\left[5/2\right]_{5/2}$ transition and determine the hyperfine structure constant for the $^1D\left[5/2\right]_{5/2}$ state in $^{171}$Yb$^+$ to be $A\left(^1D\left[5/2\right]_{5/2}\right) = -107(6)$ MHz.